Strawberry Rhubarb Crumble Bars are a sweet and tangy treat that perfectly balances juicy strawberries with the unique tartness of rhubarb. The crumbly, buttery crust and topping add a lovely crunch that makes every bite satisfying. These bars are like summer in dessert form—bright, fresh, and just a little bit nostalgic.
I always find that these bars bring a smile to everyone’s face, probably because the combination of strawberries and rhubarb feels both familiar and special. I love how the crumble topping stays crumbly even after baking, giving a nice texture contrast to the soft filling underneath. If you haven’t tried rhubarb before, this is a gentle introduction to its tangy flavor in a way that feels comforting and delicious.
My favorite way to enjoy these bars is slightly warmed with a scoop of vanilla ice cream on top. It’s like a little celebration for your taste buds! They’re wonderful for picnics, potlucks, or just a homemade dessert to brighten up any day. Whenever I bake these, the whole kitchen fills with a sweet and cozy aroma that makes waiting for them to cool so hard—but so worth it!
Key Ingredients & Substitutions
Rhubarb & Strawberries: Fresh rhubarb and strawberries give these bars their bright, tangy-sweet flavor. If rhubarb is hard to find, you can swap in tart green apples for a similar zest. Frozen fruit works too but thaw and drain excess liquid first.
Rolled Oats & Flour: These create the crumbly base and topping. You can try oat flour or gluten-free flour blends to make it gluten free, but keep the oats for texture. Quick oats might make the crumble less chunky.
Butter: Melted butter is key to a rich, tender crumb. For dairy-free, substitute with coconut oil or a vegan butter alternative—just note the flavor difference.
Sugars & Cornstarch: Brown sugar adds moisture and depth, while cornstarch helps thicken the berries so the filling isn’t soggy. You can use arrowroot for a cornstarch substitute if needed.
How Do I Get the Perfect Crumble Texture?
This crumbly topping hinges on mixing the butter evenly with dry ingredients without overworking it. Start with melted butter poured over the flour, oats, sugar, baking soda, and salt.
- Stir gently with a fork or spatula, just until the mixture looks like coarse crumbs that hold shape when squeezed.
- Set aside some crumbs for topping, press the rest firmly for the crust.
- Careful not to press too hard or overmix, or the crumb will get dense rather than light and flaky.
- Sprinkle the topping loosely over the fruit to keep it crumbly after baking.
Baking at 350°F until golden lets the topping crisp up while the fruit filling bubbles underneath. Let the bars cool fully before slicing so the filling firms up nicely.
Equipment You’ll Need
- 9×13-inch baking pan – I prefer this size because it’s perfect for even layers and easy to cut into bars.
- Mixing bowls – for combining the crumble ingredients and the fruit filling, making prep straightforward.
- Measuring cups and spoons – to measure precisely for the perfect balance of ingredients.
- Spatula or wooden spoon – ideal for mixing the crumble topping and fruit mixture smoothly.
- Oven – to bake everything until golden and bubbly, so make sure it’s preheated properly.
- Parchment paper (optional) – helps prevent sticking and makes cleanup easier.
Flavor Variations & Add-Ins
- Protein Boost: Add chopped nuts like almonds or walnuts on top for crunch and extra flavor.
- Extra Fruit: Incorporate blueberries, raspberries, or blackberries into the filling for more variety and color.
- Spice It Up: Mix in a pinch of cinnamon or ginger into the crumble for warm, cozy notes.
- Dairy-Free Version: Use coconut oil instead of butter for a dairy-free crumble that’s just as tasty.
Strawberry Rhubarb Crumble Bars
Ingredients You’ll Need:
For the Crust and Topping:
- 1 cup (2 sticks) unsalted butter, melted
- 1 1/2 cups all-purpose flour
- 1 1/2 cups old-fashioned rolled oats
- 1 cup packed light brown sugar
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
For the Filling:
- 3 cups chopped rhubarb
- 2 cups chopped fresh strawberries
- 3/4 cup granulated sugar
- 1 tablespoon cornstarch
- 1 tablespoon fresh lemon juice
- 1 teaspoon vanilla extract
Optional Topping:
- Coarse sugar for sprinkling on top
How Much Time Will You Need?
This recipe takes about 15 minutes to prepare and about 45-50 minutes to bake. Allow extra time to cool completely for about 1 hour before slicing the bars.
Step-by-Step Instructions:
1. Make the Crust and Topping Mixture:
Preheat your oven to 350°F (175°C). Line a 9×13-inch baking pan with parchment paper or lightly grease it. In a large bowl, mix together the flour, oats, brown sugar, baking soda, and salt. Pour in the melted butter and stir gently until the mixture is crumbly and holds together when pressed.
2. Prepare the Crust:
Reserve about 1 1/2 cups of the crumble mixture for the topping. Press the rest evenly into the bottom of the baking pan to form a firm crust layer.
3. Prepare the Fruit Filling:
In another bowl, combine the chopped rhubarb and strawberries with granulated sugar, cornstarch, lemon juice, and vanilla extract. Stir until everything is well mixed.
4. Assemble the Bars:
Spread the fruit filling evenly over the crust in the pan. Sprinkle the reserved crumble mixture evenly over the fruit layer. If you want added crunch and sparkle, sprinkle some coarse sugar on top.
5. Bake the Bars:
Bake in the preheated oven for 45-50 minutes, or until the top is golden brown and the fruit filling is bubbling. Remove from the oven and allow to cool completely on a wire rack.
6. Serve and Store:
Once cooled, cut the bars into squares. Store them in an airtight container at room temperature for up to 3 days, or refrigerate to keep them fresh longer. They’re delicious served slightly warmed or at room temperature.
Can I Use Frozen Fruit Instead of Fresh?
Yes! Just be sure to thaw the frozen strawberries and rhubarb completely and drain any excess liquid before mixing. This helps prevent soggy bars.
How Do I Store Leftover Bars?
Store leftovers in an airtight container at room temperature for up to 3 days. For longer freshness, keep them refrigerated and bring to room temperature before serving.
Can I Substitute Butter in This Recipe?
Absolutely! You can use coconut oil or vegan butter to make these bars dairy-free. Keep in mind the flavor and texture might be slightly different but still delicious.
Can I Make These Bars Ahead of Time?
Yes! You can prepare and bake the bars a day in advance. Store them properly and reheat slightly before serving if you like them warm.
