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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.

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.

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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 1/2 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

Looking for more rhubarb recipes? Full of tender apples, beautifully citrusy rhubarb, and crowned with a classic brown sugar oat crisp topping, Apple Rhubarb Crisp blends seasons together in sweet tart harmony. It’s different and it’s delightful!

4.68 from 50 votes

Rhubarb Crunch

Avatar photoMary Younkin
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
Servings: 9 servings
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Ingredients 

  • 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

Instructions 

  • Preheat oven to 350° F. In a medium bowl, combine the flour, oatmeal, brown sugar, melted butter and cinnamon until crumbly. Press 1/2 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 1/2 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.

Nutrition

Serving: 1 piece | Calories: 370 kcal | Carbohydrates: 63 g | Protein: 3 g | Fat: 13 g | Saturated Fat: 8 g | Polyunsaturated Fat: 4 g | Cholesterol: 34 mg | Sodium: 103 mg | Fiber: 2 g | Sugar: 46 g

Nutrition information is automatically calculated, so should only be used as an approximation.

{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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109 Comments

  1. Tony Corradi says:

    5 stars
    Looks great…love rhubarb

    1. Mary says:

      Glad to hear it, Tony. I hope you love the recipe. Enjoy, and happy baking!

  2. 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?

    1. 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.

      1. 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.

  3. Lynn Kindopp says:

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

    1. Mary says:

      This will work nicely with either of those, Lynn.

  4. Judy Harris says:

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

    1. Mary says:

      I’m so glad you’re enjoying the rhubarb crunch, Judy.

  5. nina j hawes says:

    print button does not capture recipe

    1. 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!

  6. Shell Phelps says:

    5 stars
    Can’t wait to try

    1. Mary says:

      I hope you love the rhubarb crunch, Shell.

  7. Kurly says:

    5 stars
    I make this with 2 cups of blueberries added to thickened sugar mixture. It’s the best!!

    1. Mary says:

      I have never tried that combination, Kurly. But sweet and tart works I am definitely going to try it!

  8. Lois says:

    there is no amount of water mentioned in this recipe, to make the syrup with.

    1. Mary says:

      The recipe calls for 1 cup of water, Lois.

  9. 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!

    1. Mary says:

      Sounds delicious, Mo.

  10. 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.

    1. 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.