Strawberry Rhubarb Crumb Bars with Buttery Oat Topping

Name: Strawberry Rhubarb Crumb Bars
Prep time: 2 h 15 min
Cook time: 50 min
Total time: 3 h 5 min
Cuisine: American
Ingredients: All purpose flour, 1 1/3 cups; Baking soda, 1/2 teaspoon; Kosher salt, 1/4 teaspoon; Old fashioned rolled oats, 1 1/3 cups; Brown sugar (packed), 1/2 cup; Granulated sugar, 1/2 cup (plus 1/3 cup for filling); Unsalted butter (melted), 3/4 cup; Vanilla extract, 2 teaspoons; Fresh strawberries (diced), 1 3/4 cups; Fresh rhubarb (diced), 1 1/2 cups; Lemon juice, 1 tablespoon; Cornstarch, 1 tablespoon

By:

Ruby Bennett

Published:

June 8, 2026

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Strawberry Rhubarb Bars Ingredients

Let me tell you, the ingredient list for these Strawberry Rhubarb Crumb Bars is short, simple, and full of things you probably already have in your pantry. No mixer required, which means less cleanup and more time to enjoy that buttery oat aroma filling your kitchen.

Ingredient	Amount
All purpose flour	1 1/3 cups
Baking soda	1/2 teaspoon
Kosher salt	1/4 teaspoon
Old fashioned rolled oats	1 1/3 cups
Brown sugar (packed)	1/2 cup
Granulated sugar	1/2 cup (plus 1/3 cup for filling)
Unsalted butter (melted)	3/4 cup
Vanilla extract	2 teaspoons
Fresh strawberries (diced)	1 3/4 cups
Fresh rhubarb (diced)	1 1/2 cups
Lemon juice	1 tablespoon
Cornstarch	1 tablespoon

Note: If you can find it, use fresh rhubarb from the farmers market, the stalks are usually more tender and flavorful. And remember: rhubarb leaves are toxic, so trim them off and discard right away.

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How to Make Strawberry Rhubarb Bars

These bars come together in a flash. The crumb mixture does double duty as both the crust and the topping, so you only need to make one batch of that buttery oat goodness. I absolutely love how the sweet strawberries and tart rhubarb bubble up through the golden crumble.

Instructions

Preheat your oven to 350°F. Butter a 9×9 inch baking dish (or line it with parchment paper for easy removal).

For the crumb layer: In a large bowl, whisk together 1 1/3 cups flour, 1/2 teaspoon baking soda, 1/4 teaspoon salt, 1 1/3 cups old fashioned oats, 1/2 cup brown sugar, and 1/2 cup granulated sugar. Pour in 3/4 cup melted butter and 2 teaspoons vanilla extract. Stir with a fork until the mixture looks like coarse crumbs. Press about two thirds of the crumb mixture firmly into the bottom of the prepared dish. Set the remaining third aside for the topping.

For the filling: In a separate bowl, toss 1 3/4 cups diced strawberries and 1 1/2 cups diced rhubarb with 1 tablespoon lemon juice. In a small bowl, whisk together 1/3 cup granulated sugar and 1 tablespoon cornstarch. Pour the sugar mixture over the fruit and stir gently until evenly coated. Spread the fruit filling over the pressed crust.

Sprinkle the reserved crumb mixture evenly over the fruit. Bake for 45 to 50 minutes, until the top is golden brown and the filling is bubbly around the edges. Let the bars cool completely on a wire rack before cutting, this is crucial, because the filling needs time to set. If you cut too soon, you will end up with a delicious but messy puddle.

Can I Use Frozen Fruit in This Recipe?

Absolutely, yes! Frozen fruit works beautifully here. If you are using frozen rhubarb, thaw it first and drain off any excess liquid so your filling doesn’t turn watery. The same goes for frozen strawberries, thaw and drain, then pat them dry gently with a paper towel. You might lose a tiny bit of fresh flavor, but honestly, when baked into these bars with that buttery oat crumble, nobody will notice. Just add an extra minute or two to the baking time if the fruit is still cold.

How to Store Strawberry Rhubarb Crumble

Here is the secret to keeping those bars perfectly crisp: store them in an airtight container at room temperature. I know it is tempting to refrigerate leftovers, but the cold will make the crumb topping go soft and mushy. They will stay fresh on the counter for up to 2 days. If you need to keep them longer, pop them in the fridge for up to 5 days, just know the topping will lose some crunch. For longer storage, wrap each bar tightly in plastic wrap and then foil, and freeze for up to 3 months. Thaw at room temperature before serving.

Pro tip: If you freeze the bars, reheat them in a 300°F oven for about 10 minutes to bring back that crisp, buttery topping.

Tips for the Best Strawberry Rhubarb Crisp

Use old fashioned oats, not quick or steel cut. Quick oats turn mushy and steel cut oats stay too chewy. Old fashioned oats give the perfect texture.
Let the bars cool completely before cutting. At least 2 hours on the counter, or speed it up in the fridge. This prevents the filling from running everywhere and also saves your tongue from a hot fruit burn.
Serve with vanilla ice cream or whipped cream. The cold creaminess against the warm, tart sweet bars is pure magic.
Add a pinch of cinnamon or some orange zest to the crumb mixture for an extra layer of flavor. I love a little orange zest with the rhubarb.
Make them dairy free by swapping the butter with melted coconut oil. Use the same amount and proceed as usual.
Try a gluten free version with a 1 to 1 gluten free flour blend and certified gluten free oats. The texture will be slightly more tender but still delicious.
For a fun twist, serve the bars with yogurt and a drizzle of honey for breakfast (no judgment here, they are basically oatmeal, right?).

If you love this style of fruity crumb bars, you have to try my amish oatmeal rhubarb bars, they are another favorite in my kitchen. And for a simpler version without the oat crumble, check out this strawberry rhubarb crumble.

Tips for the Best Strawberry Rhubarb Crisp

Frequently Asked Questions

How do you make strawberry rhubarb crumb bars?

Start by making a buttery oat crust and crumb topping. Press most of the mixture into a baking dish, then layer with a strawberry rhubarb filling (fresh or frozen fruit, sugar, cornstarch, lemon juice). Sprinkle remaining crumb mixture on top and bake until golden and bubbly.

Can I use frozen rhubarb for strawberry rhubarb bars?

Yes, frozen rhubarb works well. There is no need to thaw it first. Toss the frozen rhubarb with sugar and cornstarch, then proceed with the recipe. You may need to add a minute or two to the baking time.

Do I need to peel rhubarb for bars?

No, peeling is not necessary. Simply wash the stalks and trim the ends. For older, thicker stalks you can peel the tough outer layer, but most fresh rhubarb is fine unpeeled.

How should I store strawberry rhubarb crumb bars?

Store the bars in an airtight container at room temperature for up to 2 days or in the refrigerator for up to 5 days. For longer storage, freeze them for up to 3 months.

Can I freeze strawberry rhubarb crumb bars?

Yes, these bars freeze well. Cool completely, wrap tightly in plastic wrap and foil, then freeze. Thaw in the refrigerator or at room temperature before serving.

Why are my strawberry rhubarb bars soggy?

Sogginess can happen if the filling has too much liquid or if the bars are underbaked. Use cornstarch to thicken the fruit mixture and bake until the filling is bubbling and the topping is golden. Let them cool completely before cutting.