Rhubarb Crunch Recipe for a Family Favorite Spring Dessert

Name: Rhubarb Crunch
Prep time: 30 min
Cook time: 1 h
Total time: 1 h 15 min
Cuisine: American
Ingredients: 1 cup all purpose flour; 3/4 cup old fashioned oats; 1 cup brown sugar (packed); 1/2 cup melted butter; 1 teaspoon ground cinnamon; 4 cups diced rhubarb (about 1 pound, from about 6 stalks); 1 cup granulated sugar; 2 1/2 tablespoons cornstarch; 1 cup water; 1 teaspoon vanilla extract

By:

Ruby Bennett

Published:

June 6, 2026

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Ingredients

This old fashioned Rhubarb Crunch uses simple pantry ingredients. Here is what you will need:

1 cup all purpose flour
3/4 cup old fashioned oats
1 cup brown sugar (packed)
1/2 cup melted butter
1 teaspoon ground cinnamon
4 cups diced rhubarb (about 1 pound, from about 6 stalks)
1 cup granulated sugar
2 1/2 tablespoons cornstarch
1 cup water
1 teaspoon vanilla extract

Most of these are common staples you likely have on hand. If you are using frozen rhubarb, just thaw it and drain off the extra liquid before measuring. Remember, only use rhubarb stalks; the leaves are toxic due to oxalic acid.

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Directions

Making this rhubarb crunch is easier than you might think.

Follow these straightforward steps and you will have a bubbling, golden dessert in no time.

Step 1: Preheat and prep

Preheat your oven to 350 degrees F. Grease a 9×9 inch baking dish with butter or nonstick spray. Set it aside while you make the crumble.

Step 2: Make the crumble

In a medium bowl, whisk together the flour, oats, brown sugar, and cinnamon.

Pour in the melted butter and stir with a fork until the mixture looks like coarse crumbs. A pinch of salt at this point will brighten all the flavors.

Step 3: Create the crust

Press half of the crumb mixture firmly into the bottom of your prepared dish.

This will be your buttery crust, so make it even and compact.

Step 4: Add the rhubarb

Spread the diced rhubarb evenly over the crust.

Do not worry if it piles up; it will settle as it bakes. Do not peel the rhubarb; the skin adds lovely color and fiber.

Step 5: Make the sauce

In a small saucepan, combine the granulated sugar, cornstarch, water, and vanilla.

Cook over medium low heat, stirring constantly, until the sauce thickens and turns clear, about 3 to 5 minutes. This warm vanilla sauce is what makes the crunch so special.

Step 6: Pour the sauce

Pour the hot sauce evenly over the rhubarb, letting it seep down between the pieces.

Do not stir; just let it find its way.

Step 7: Add the topping

Sprinkle the remaining crumb mixture over the top.

Do not press it down; you want a light, crumbly topping that will turn golden in the oven.

Step 8: Bake

Bake for 1 hour, until the topping is golden brown and the rhubarb filling is bubbly around the edges.

Let the dish cool for at least 10 to 15 minutes before serving so the filling sets up properly.

Tips and Variations

Once you master the basic recipe, try these fun twists. Swapping 1 to 2 cups of rhubarb with fresh or frozen strawberries makes a delightful strawberry rhubarb crunch. You can also add 1/2 cup chopped pecans or walnuts to the topping for extra crunch. For a flavor change, use almond extract or lemon zest instead of vanilla. If your rhubarb stalks are very thick and tough, microwave them for a minute or two to soften before adding to the dish. These simple tweaks keep the recipe interesting all season long.

For another delicious rhubarb treat, try my Amish Oatmeal Rhubarb Bars With Crumb Topping. And if you love the strawberry rhubarb combination, you will enjoy this Strawberry Rhubarb Crumble.

Storage Tips

This rhubarb crunch stores beautifully and actually tastes even better the next day as the flavors meld. Here is how to keep it:

Storage Method	Duration	Reheating
Room temperature (covered)	Up to 2 days	None needed
Refrigerator (airtight container)	Up to 5 days	Microwave or oven at 300 degrees F
Freezer (freezer safe container)	Up to 3 months	Thaw or reheat at 300 degrees F until warm

To reheat, pop individual servings in the microwave or warm the whole dish in a 300 degree F oven for about 10 minutes. It is a freezer friendly dessert, perfect for potlucks and unexpected guests.

Frequently Asked Questions about Rhubarb Crunch

What is rhubarb crunch?

Rhubarb crunch is a baked dessert consisting of a layer of sweetened rhubarb filling topped with a buttery oat crumble. It is similar to a crisp but often has a denser, more cookie like topping.

How do you make rhubarb crunch?

Toss chopped rhubarb with sugar and a thickener like cornstarch or flour. Spread in a baking dish, then top with a mixture of oats, flour, brown sugar, butter, and optional nuts. Bake at 350F until the filling bubbles and the topping is golden, about 40 to 50 minutes.

Can you use frozen rhubarb for rhubarb crunch?

Yes. Use frozen rhubarb straight from the freezer without thawing to prevent excess liquid. You may need to add a little extra thickener and increase baking time by 5 to 10 minutes.

Why is my rhubarb crunch runny?

Runny filling usually means too much liquid from the rhubarb or not enough thickener. Older rhubarb or previously frozen fruit releases more juice. Ensure you use at least 2 tablespoons of cornstarch or flour per 4 cups of rhubarb.

How do you thicken rhubarb crunch filling?

Toss the rhubarb with a starch such as cornstarch, arrowroot, or tapioca before adding sugar. Let the mixture sit for 10 minutes to draw out juice, then stir again before pouring into the dish. This helps the starch distribute evenly.

Can you freeze rhubarb crunch?

Yes, bake it first, then cool completely. Wrap tightly in foil or plastic wrap and freeze for up to 3 months. Reheat directly from frozen in a 350F oven until warmed through, about 20 to 30 minutes.

Rhubarb Crunch Recipe for a Family Favorite Spring Dessert

Ingredients