Rhubarb Crunch

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Old-fashioned Rhubarb Crunch begins with a brown sugar oatmeal crumble layer that is topped with fresh rhubarb and then it is finished with a second layer of crumble over the top.

The Strawberry Rhubarb Fruit Crisp is an ever-popular dessert in the summertime and this crunch variation takes it to an even tastier new level.

Rhubarb Crunch

I hope you’re enjoying as beautiful of a spring as we are! I’m so happy to be deep into rhubarb season and I’m looking forward to more fruit desserts through the summer as well.

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I’m excited to be working on more rhubarb recipes again this year. We have so many to share and I’m working through a list of them for you!

So far, I’ve shared a Rhubarb Crisp, Rhubarb Cake with Butter Sauce, Rhubarb Bars, Old Fashioned Rhubarb Pie and the Double Crumb Rhubarb Coffee Cake.

This No Churn Rhubarb Ice Cream from Our Table for Seven and this Strawberry Rhubarb Galette from 365 Days of Baking are also on my list to try soon.

What is a Rhubarb Crunch?

A fruit crunch is similar to fruit crisps, but it has an oatmeal crumble layer on the bottom as well as a top.

Similar to a bar, but still gooey enough to eat with a spoon. It’s perfect with a scoop of vanilla ice cream or a dollop of freshly whipped cream.

A generous amount of brown sugar in the crumb layers and plenty of white sugar for the filling nicely balances the tartness of the rhubarb.

Old Fashioned Rhubarb Crunch

How to Make Rhubarb Crunch? 

First you’ll start by making a brown sugar oatmeal crumb layer. Melt some butter and add oatmeal, flour and brown sugar. Mix until crumbly.

Press half of these crumbs on the bottom of the pan. Then top with some chopped rhubarb. You can use fresh or frozen.

If you choose to use frozen rhubarb, you’ll want to check out the section below on how to use frozen rhubarb in this rhubarb crunch recipe. 

Rhubarb Crunch

The next step of the recipe is what makes the rhubarb crunch unique. You boil a mixture of water, sugar and cornstarch until thickened and bubbly.

Then pour the mixture over the rhubarb in the pan. Top with the remaining half of the oatmeal crumb mixture and bake for about an hour. 

Like most fruit crisps, I think a crunch is best served warm with ice cream or whipped cream, but the leftovers are also delicious the next day, eaten cold straight from the refrigerator. 

Old Fashioned Rhubarb Crunch is a sweet and tangy favorite.

How to use frozen rhubarb in this recipe? 

You can make this recipe using fresh or frozen rhubarb.

If you choose to use frozen rhubarb thaw the rhubarb first and let any excess liquid drain off. Don’t squeeze any liquid out, just drain what naturally thaws out of the rhubarb. 

You’ll want to plan ahead to use frozen rhubarb. Depending on the temperature of the room, it takes 4-6 hours to thaw a quart of rhubarb completely.

So you may want to take it out of the freezer the night before. When in a pinch, I’ve also used the auto defrost feature on the microwave to give it a head start, just be careful not to heat it too high and cook it.

Rhubarb Crunch is an easy dessert for any occasion.

Rhubarb Crunch Recipe

  1. Preheat oven to 350° F. In a medium bowl, combine the flour, oatmeal, brown sugar, melted butter and cinnamon until crumbly. Press ½ of the crumb mixture into a greased 9 x 9 inch or 11 x 7 inch baking pan.
  2. Spread the diced rhubarb in the pan. In a small saucepan, combine the white sugar, water and cornstarch. Bring to a boil over low heat. Continue to cook and stir until the mixture is thick and clear. Pour the sugar mixture over the rhubarb in the baking pan. Top with the remaining crumb mixture.
  3. Bake for 1 hour. Cool at least slightly before serving. To serve, cut into squares and top with ice cream or whipped cream. Best served warm.
Old Fashioned Rhubarb Crunch
Old Fashioned Rhubarb Crunch

Rhubarb Crunch

4.67 from 45 votes
A little different than rhubarb crisp, this recipe for old fashioned rhubarb crunch has a brown sugar oatmeal crumble layer on the bottom as well as the top. 
Prep Time: 20 minutes
Cook Time: 1 hour
Additional Time: 30 minutes
Total Time: 1 hour 50 minutes
Course: Dessert
Cuisine: American
Servings: 9 servings


  • 1 cup all purpose flour
  • 3/4 cup quick cooking oatmeal
  • 1 cup brown sugar
  • 1/2 cup melted butter
  • 1 teaspoon cinnamon
  • 4 cups diced rhubarb
  • 1 cup white sugar
  • 1 cup water
  • 2 tablespoons cornstarch
  • Vanilla ice cream or whipped cream for serving


  • Preheat oven to 350° F. In a medium bowl, combine the flour, oatmeal, brown sugar, melted butter and cinnamon until crumbly. Press ½ of the crumb mixture into a greased 9 x 9 inch or 11 x 7 inch baking pan.
  • Spread the diced rhubarb in the pan. In a small saucepan, combine the white sugar, water and cornstarch. Bring to a boil over low heat. Continue to cook and stir until the mixture is thick and clear. Pour over the rhubarb in the baking pan. Top with the remaining ½ of the crumb mixture.
  • Bake for 1 hour. Cool at least slightly before serving. To serve, cut into squares and top with ice cream or whipped cream. Best served warm.


Serving: 1piece · Calories: 370kcal · Carbohydrates: 63g · Protein: 3g · Fat: 13g · Saturated Fat: 8g · Polyunsaturated Fat: 4g · Cholesterol: 34mg · Sodium: 103mg · Fiber: 2g · Sugar: 46g
Tried this recipe?Mention @chocolatewithgrace or tag #chocolatewithgrace!

{originally published 4/11/19 – recipe notes and photos updated 5/25/21}

Rhubarb Crunch is an old-fashioned dessert that we all love!

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  1. Jen says

    This totally reminds me on my childhood. My mom used to make this for us all the time. I just love rhubarb.

  2. Julie says

    5 stars
    My grandkids and friend love this. I now am making 3 more using your recipe. This recipe has made my daughter a rhubarb love. Thank you

  3. Marguerite says

    5 stars
    this is the recipe I had and lost – so glad to have found it here – (I reduce the sugar in the water-cornstarch mixture to a little less than three-quarter cup – and it’s still plenty sweet

        • wendy says

          2 stars
          Got to the end of making this and… Water? It’s not in ingredient list- how much? I only put a few teaspoons as sugar was melting & liquify but don’t think it was enough as it hardened as I poured into pan and after 8 min never did turn clear. Can you clarify? I’d like to keep this recipe if i can have that info. Thanks

          • Mary says

            Hi, Wendy! In the future, water is in the ingredient list, in the recipe card. You should add 1 cup of water alongside the cup of white sugar and two tablespoons of cornstarch when creating the sweet sauce to pour over the rhubarb.

        • Gwendelyn says

          Hello, very excited to try this recipe. Does it freeze well? To make ahead for event. How long is it good to stay in the fridge?

          • Mary says

            This will keep nicely in the fridge for a day or two. While it will freeze, I wouldn’t typically make it in advance and freeze it for an event.

  4. Shelley W. says

    This looks very much like a recipe my Grandma made when I was a child, but she used rhubarb paired with cranberries. I seem to remember she put the cranberries on top of the rhubarb pieces. it was delicious too, though just slightly tart. I do love that sweet/tart crossover. She paired cranberry, rhubarb and strawberries cooked like a compote with a wee bit of ginger and nutmeg and then tucked into pre-baked shortbread tart crusts, topped with a little cinnamon whipped cream.. Gee, now I’m drooling, I wish Grandma was still alive. Thank you sooo much for the recipe and for bringing back some lovely memories. Happy baking!

  5. Jacq says

    Okay, followed the recipe, had doubts at stage 2, looked like the picture but completely inedible. If I try again will be without cornflour and half the sugar. Seriously, 3 cups?

    • Sabrin says

      Never got clear. When it was really getting goopy I decided to take it off. It’s baking now. Was looking through comments to see if anyone else had it not turn perfectly clear.

      • Sharon K says

        3 stars
        Cornstarch is fussy. The 2 Tbsp sounds a bit much for 1C of water but then have to take into consideration that the rhubarb the rhubarb will make some juice too.
        Also, you have to be sure cornstarch is well mixed into the COLD water. Can’t add it to hot water EVER. May be the reason it wasn’t the consistency needed.
        I would mix the cornstarch into the COLD cup of water before adding it to the sugar ( which I’d cut down to 2/3 C) in the pan before turning heat on under it. Bring to boil stirring often; turn down to simmer and stir for couple minutes. Take it off the heat.

  6. Barb says

    5 stars
    This is absolutely delicious. My husband couldn’t stop complimenting me on the recipe. Made just like recipe but only had 3 cups of rhubarb. Still wonderful.

  7. Daphne says

    5 stars
    This rhubarb crunch is absolutely delicious! My nephew, who is 10 years old, requested the recipe so that he could make it for when they had company coming over 🙂 It’s a definite keeper!!

    • Mary says

      That should work fine, Taylor. The crunch will have a slightly more defined texture this way. I use both kinds of oats when I make this.

  8. Pat Gerbrandt says

    I’m about to bake this. In the bottom version of the ingredients, water is included, but that line is missing from the ingredients at the top of the page and on the photo.

    • Mary says

      Yes, you do need the water. It isn’t always listed with ingredients you’ll need to gather or have on hand, but it is in the recipe card and instructions. Happy baking!

  9. Jennifer McAllister says

    5 stars
    This was delicious. I did make it with oat flour (I’m celiac) and I put all the crumbs on top. It baked in about 45-50 minutes. Will make this recipe again soon.

    • Mary says

      Jennifer – Thank you so much for sharing. I always appreciate knowing what adjustments work for people with different restrictions.

  10. Jennifer says

    5 stars
    I made a double batch of this deliciousness tonight and it was absolutely the best tart and sweetness mixed together in …….yum! It was a big hit with my family. It was so simple to make and worth every bite! 😋

    • Mary says

      Jennifer – The tart and sweet of this recipe is so good. I am glad it was a hit with your family.

  11. Marcy says

    Are you not supposed to refrigerate the rhubarb crisp? The bottom crust got hard and stuck to the glass pan after I put it in the fridge. Other than that it tasted great and I will make again

      • Cassey Melde says

        Baking this recipe now. I did use rhubarb and strawberries. It looks and smells amazing! I see the comments saying not to refrigerate it. Do you think that will be ok with strawberries too?

        • Mary says

          Hi, Cassey! You can refrigerate the rhubarb crunch, but it’s not necessary. It should keep for a few days on the counter if you use strawberries. I hope you love the recipe!

  12. Jo says

    5 stars
    I added pecans and took it right on over the top from it’s already delicious state! Thanks for the best rhubarb recipe!

  13. Wendy says

    5 stars
    Excellent recipe…so easy…and so delicious! I made mine in a 10×10 pan which worked well too ( more servings!)

  14. Robin says

    5 stars
    I’ve been eating rhubarb crunch for over 50 years. My mom made it and I make it (and strawberry rhubarb crunch) for my family. We took both to a family reunion on my husband’s side. They were both a huge hit!

  15. Angie says

    5 stars
    Made this last night. I used one and 3/4 cup of sugar because two seemed like a lot. It turned out perfect. Still a little bit tart which we like.

    • Mary says

      Perfect! I am glad you were able to adjust the recipe to suit your tastes. I love a slightly tarter rhubarb as well, Angie.

  16. Mo says

    5 stars
    My sister added a couple cups of fresh blueberries and used old fashioned oats. (Used frozen rhubarb). Baked 55 min. Best I have had, ever!

    • Mary says

      Hi, Nina! Sorry to hear that you’re having a technical issue of some sort. Did you click the print button in the recipe card, then click print at the top of the new page that opens? You should be redirected to a print page. If that button doesn’t work, try this link: https://chocolatewithgrace.com/wprm_print/4461. I hope you love the rhubarb crunch!

  17. Judy Harris says

    5 stars
    This is my go to recipe for rhubarb….fast easy and absolutely delicious….. highly recommend it for everyone

  18. Lynn Kindopp says

    Have you ever used this recipe substituting either all apples or all saskatoons (much like blueberries)?

  19. Lynn says

    4 stars
    I doubled recipe and used 9×13 pan. My bottom crumble was so hard to get out of pan. I did refrigerate. Any ideas on what I did wrong?

    • Mary says

      Hi, Lynn! Did you still spread about half the oat mixture across the bottom of the pan, or is there a chance it might have been less? And were any ingredients substituted or omitted? Sorry you had trouble getting the rhubarb crunch out of the pan.

      • Carol says

        4 stars
        I had the same problem with the bottom crust. Baked the night before and took to family reunion the next day. Did not refrigerate. Sprayed glass pan before putting crust in. Packed the crust a little bit.

  20. Sharon says

    5 stars
    I had a couple “ Diamond Pecan Ready Made Crust”. I made the recipe as listed and used the pre made crust as the bottom . It was phenomenal. I was able to make two pies. Keeping this recipe.

    • Mary says

      I’m so glad you loved the recipe, Sharon, and that you were able to make the pre made crust work well with the dish. Enjoy the pies, and happy baking!

  21. Rayanna says

    5 stars
    I got this recipe from my husbands auntie. There isn’t A better recipe!! I’ve tweaked it by putting strawberries in it or raspberries. You can also use the same crust and topping recipe and change fruit to apple, peach or pears. Core, peel, and slice thin. Always a hit at get togethers!

  22. Sheila says

    5 stars
    Tried with fresh blueberries first, made a second time with raspberries and strawberries it’s a hit with the kids and adults here! We are making this once a week and will continue once our wild berries bare fruit this summer and fall! Thank you for the recipe!

  23. Julie says

    5 stars
    Everyone that tried this loved it. My grandkids usually don’t eat rhubarb but this was a big hint. I doubled the crust absolutely a hit. Made it 3 times in a week.

  24. Kim says

    5 stars
    My mom has been making this exact recipe for at least 40 years. It is now down to me to make it for her. It is absolutely delicious!

  25. Judy says

    5 stars
    We loved this. The rhubarb looks deliciously red in this recipe, perhaps due to the sugar and water mixture. The presentation is pretty and the dessert is easy to cut and serve. Keeps and tastes great the next day. I did only use 3/4 cup white sugar and it was still very sweet. Topped with ice cream.

  26. Sharon says

    5 stars
    I’ve grown up eating this and now it’s the first thing I make every rhubarb season. I add vanilla to the syrup after it thickens, and I sprinkle a little strawberry Jello over the rhubarb before pouring the syrup. It helps keep the dish from becoming too runny, and adds a tiny bit of sweetness to the rhubarb filling.

    • Mary says

      I’ve never tried adding jello to the filling, Sharon. I’m thrilled you’re enjoying the recipe.

  27. Donna Guasco says

    5 stars
    I made this for a group that I cook for every Wednesday. They devoured it! Served it warm with strawberry whipped cream. Also added strawberries to the Rhubarb when I cooked it down. Will make this again!!!