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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.

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.

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.

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.

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 Recipe
- 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 the sugar mixture over the rhubarb in the baking pan. Top with the remaining 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.

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!

Rhubarb Crunch
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
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}















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!
Excellent recipe…so easy…and so delicious! I made mine in a 10×10 pan which worked well too ( more servings!)
I added pecans and took it right on over the top from it’s already delicious state! Thanks for the best rhubarb recipe!
Jo – That sounds wonderful.
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
Marcy – No this does not need refrigerated but should be consumed within 1-2 days.
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?
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!
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! ?
Jennifer – The tart and sweet of this recipe is so good. I am glad it was a hit with your family.
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.
Jennifer – Thank you so much for sharing. I always appreciate knowing what adjustments work for people with different restrictions.
Made this exactly as written and it was so delicious! Everyone loved it!
Gail – So glad to hear that!
Delish! Made it for family BBQ – a real hit with everyone. Thanks
I’m so glad you like it, Nicky!
Could you use frozen rhubarb?
That will work nicely, Alison!
Could I make this and freeze it before baking at a later date?
I’ve never tried that, Heather.