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Best Rhubarb Crunch Recipe (Old-Fashioned Dessert)

Our Rhubarb Crunch recipe has the perfect balance of a sweet-tart rhubarb filling under the delightful crunch of a buttery crumble topping. This incredibly quick and easy recipe is a delicious way to enjoy fresh rhubarb flavor.

Close-up image of rhubarb crunch on a plate topped with ice cream.

As soon as rhubarb season rolls around our old-fashioned rhubarb crunch recipe is one of the first recipes to hit the oven. We’ll show you how easy this sweet dessert recipe is to make.

What is Rhubarb?

A delicious Spring crop, rhubarb looks, feels, and crunches like a pink version of celery. Even though it’s mistaken as a fruit, it’s a vegetable. It can be eaten raw but it is very tart. Please note that the leaves are poisonous to humans and should never be eaten.

When baked with sweeteners, it makes delicious desserts while it is in season. Out of season, fresh rhubarb can be difficult to find in the grocery store but many of our rhubarb desserts can be adapted using frozen.

What is Rhubarb Crunch?

This is basically like a fruit crisp recipe, but the crunchy oat streusel topping gets crunchier. You may have heard a similar recipe called Rhubarb Crisp.

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Ingredients you’ll need for Rhubarb Crunch

Top down view of ingredients used to make rhubarb crunch including brown and white sugar, flour, cinnamon, butter, vanilla, oats, rhubarb, cornstarch, and water.
Rhubarb Crunch Ingredients
  • Fresh Rhubarb. Cleaned and diced rhubarb stalks.
  • Granulated White Sugar. Balances out the tartness of the rhubarb.
  • Cornstarch. Used for thickening.
  • Water. Added to the cornstarch and sugar to make a syrup.
  • Vanilla Extract.
  • All-Purpose Flour. You can use gluten-free, one-for-one, all-purpose flour instead if needed.
  • Rolled Oats. Old-fashioned rolled oats work best for the texture you want with this recipe.
  • Brown Sugar. Dark or light brown sugar will work.
  • Ground Cinnamon. I love Saigon cinnamon for a flavor punch.
  • Butter. You could use a butter substitute as needed, but the flavor will be lacking.

How To Make Rhubarb Crunch

Please note, that the printable recipe card has ingredient quantities, complete instructions, and nutritional information. The following is a quick overview of the recipe.

Step One. Get everything ready.

Go ahead and preheat your oven and spray your pan. Clean and dice the rhubarb and place it in the baking dish.

Step Two. Cook the thickener.

Add the water, sugar, and cornstarch to a saucepan. Whisk it to combine, and heat until thickened. Add the vanilla.

A saucepan filled with water, sugar, and cornstarch
Combine water, sugar, and cornstarch

Step Three. Combine.

Pour the syrup over the rhubarb mixture in the baking dish.

Top down view of sliced rhubarb covered with thick syrup for a rhubarb crisp recipie. Hostess At Heart

Step Four. Make the Rhubarb Crunch topping.

Combine the topping ingredients, flour, oatmeal, brown sugar, and cinnamon. Add the melted butter and combine. Spread the crumble mixture over the top of the chopped rhubarb filling.

Step Five. Bake your Rhubarb Crisp.

Bake uncovered for 35 to 45 minutes.

Top down view of a pan of baked rhubarb crisp with oat crumble topping - Hostess At Heart

What to Serve with this Recipe for Rhubarb Crunch

You can serve this tasty treat warm or cold, with whipped cream or a scoop of vanilla ice cream, or on its own. It works as a breakfast, snack, or an easy dessert.

Frequently Asked Questions

Can I use frozen rhubarb instead of fresh?

Yes, you can use frozen rhubarb. It’s best that you thaw rhubarb when baking with it. You’ll want to plan ahead because it can take several hours to thaw thoroughly. Place the frozen rhubarb in a colander set over a bowl at room temperature.

You can even thaw it overnight. Cover the top of the colander with plastic wrap so it doesn’t dry out and just dot any extra moisture from it using a paper towel. Don’t squeeze it. Too much moisture will make your rhubarb crisp runny.

How do I know the rhubarb crisp is done baking?

It will be hot and bubbly at the edges, and the top will be golden brown.

Can Rhubarb Crunch be made ahead of time?

Yes. Since it can be served warm or cold, you can make it a day ahead of time and refrigerate it.

Angled biew of two slices of oat streusel topped rhubarb dessert - Hostess At Heart

How To Reheat & Store Rhubarb Crunch

Best way to store Rhubarb Crumble

Keep leftovers refrigerated. Cover the dish with aluminum foil, plastic wrap, or a lid, which should keep for three to five days. This will keep the juices from running and making the crunch soggy.

Can I freeze Rhubarb Crunch?

Yes. Freeze a whole dish or individual servings in airtight freezer-safe containers. Thaw to serve cold.

How to reheat

Reheat individual servings of Rhubarb Crunch in the microwave for fifteen to thirty seconds to serve it warm. Reheat an entire pan of the dish in the oven at 300ºF until hot and bubbly.

Top down angled view of rhubarb crumble bars with oat crisp topping - Hostess At Heart

Hostess Tips for the Perfect Rhubarb Crunch

  • Rhubarb doesn’t need to be peeled before you use it. Remove the leaves and I also remove the lowest part of the stem.
  • The rhubarb needs to be chopped in consistent thicknesses so that the filling bakes at the same rate. We’ve found that 1/2-inch works well. Thinner and your filling could be mushy, thicker and it may be firmer.
  • You can use more rhubarb in this recipe without adjusting the crumble amount. It’s important to cover the bottom of your baking dish.
  • While we highly recommend Old-Fashioned Oats, you can use quick oats in a pinch. Just know that you won’t get the perfect crunch of this original recipe.

If you have plenty of rhubarb, you may enjoy one of our other favorite rhubarb recipes like Rhubarb Custard Pie, Rhubarb Cake, or this tasty Strawberry Rhubarb Bread. We even have a fantastic family recipe for Rhubarb Sauce that’s great for using up a lot of extra rhubarb. And, I adore this Lemon Rhubarb Bundt Cake.

Top down view of a serving of rhubarb crunch dessert on a plate - Hostess At Heart

I hope you enjoyed this delicious recipe as much as we do. Drop me a comment below, and don’t forget to give it a star rating. ⭐⭐⭐⭐⭐. Your comments and ratings help others decide if this recipe is for them too.

Sideview of a serving of rhubarb dessert topped with oat crunch topping and a scoop of ice cream - Hostess At Heart

Rhubarb Crunch Dessert

Author: Julie Menghini
Our easy Rhubarb Crunch recipe combines the perfect balance of tart rhubarb filling and the delightful crunch of a buttery crumble topping.
5 from 1 vote
Prep Time 20 minutes
Cook Time 45 minutes
Total Time 1 hour 5 minutes
Course Dessert
Cuisine American
Keyword: Rhubarb Dessert, Rhubarb recipe
Servings: 12


  • 4 cups rhubarb chopped 1/2" thick
  • ¾ cup sugar
  • 2 tbsp cornstarch
  • 1 cup water
  • 2 tsp vanilla extract
  • 1 cup all-purpose flour
  • ¾ cup rolled oats old-fashioned
  • 1 cup brown sugar
  • 2 tsp ground cinnamon
  • ½ cup butter melted


  • Preheat the oven to 350 °F, and spray a 9×13 baking dish with non-stick cooking spray.
  • Place diced rhubarb in the bottom of the baking dish.
  • In a medium-sized saucepan, add the water, sugar, and cornstarch. Whisk together until there are no clumps of cornstarch. Heat over medium heat, stirring occasionally until thickened. Stir in the vanilla and stir to combine.
  • Pour the cornstarch mixture evenly over the rhubarb.
  • In a separate bowl, combine the flour, oatmeal, brown sugar, and cinnamon together. Mix until combined. Pour in the melted butter and stir until everything has a coating of butter and there are no large clumps. Sprinkle over the rhubarb.
  • Bake uncovered for 35 to 45 minutes.


May be served warm or cold. 
Store baked crunch dessert covered in the refrigerator. 


Calories: 259kcalCarbohydrates: 45gProtein: 2gFat: 8gSaturated Fat: 5gPolyunsaturated Fat: 0.5gMonounsaturated Fat: 2gTrans Fat: 0.3gCholesterol: 20mgSodium: 69mgPotassium: 176mgFiber: 2gSugar: 31gVitamin A: 279IUVitamin C: 3mgCalcium: 61mgIron: 1mg

Nutritional Disclaimer

This recipe was calculated using the exact brands and measurements I used to make this recipe. If you are following a strict diet please note changing anything will cause the nutritional info to change. My calculations are intended as a guide only.

Tried this recipe?Let me know how it was!

If you’re still looking for delicious fruit desserts with a delectable crunch, our apple crisp, peach crisp, and pear crisp recipes are very popular.

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Angled view of a slice of rhubarb crisp topped with vanilla bean ice cream - Hostess At Heart
5 from 1 vote
Recipe Rating

Jeff the Chef

Wednesday 15th of May 2024

I like rhubarb, but I've never made anything with it. I'm going to have to keep my eyes open to find it in the store when it's in season.

Julie Menghini

Wednesday 15th of May 2024

I hope you'll give it a try!


Tuesday 30th of April 2024

I just harvested our first batch of rhubarb, and this is in the oven; I already know it's going to be amazing; the smell is heavenly!

Tuesday 30th of April 2024

We love rhubarb season!


Monday 29th of April 2024

Excellent....thank you!

Julie Menghini

Tuesday 30th of April 2024

Thank you, Marlyse!

Laura Ashley Johnson

Monday 29th of April 2024

The smell of this alone was incredible! Truly one of my new favorite desserts! Everyone in my family loved it!

Julie Menghini

Tuesday 30th of April 2024

Thank you, Laura! I love rhubarb season.

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