These Strawberry Blueberry Crumble Bars are the ultimate easy summer dessert! With a buttery shortbread-style crust, juicy mixed berry filling, and a golden crumble topping, they taste like a berry crisp in bar form. They’re perfect for warm-weather gatherings, picnics, or your Fourth of July table – especially when served alongside my Strawberry Crumble Bars for a beautiful red, white, and blue spread.
Why You’ll Love These Strawberry Blueberry Crumble Bars
- Easy one-bowl crust and topping
- Fresh, juicy berries with the perfect balance of sweet and tangy
- Great make-ahead dessert that travels well
- Beautiful patriotic treat for the 4th of July
Ingredients & Substitutions
- Crust: The crust is buttery and soft with just the right structure to hold all that berry filling. It does get a quick bake on its own (about 12 to 15 minutes), which helps it set up so the bars slice cleanly later.
- Strawberries & Blueberries: Fresh strawberries and blueberries make up the filling. They’re tossed with sugar, cornstarch (for thickening), lemon zest, lemon juice, and vanilla. The berries soften as they bake and create that jammy, juicy center.
- Lemon Flavor: The lemon zest and juice add brightness and help balance the sweetness of the berries. They also work with the cornstarch to keep the filling from getting too loose. You can leave them out, but the flavor won’t be quite as fresh or vibrant.
- Crumble Topping: This is the golden, buttery layer that brings everything together. Made with flour, brown sugar, and melted butter, it bakes up lightly crisp and adds the perfect texture contrast to the soft filling.
- Confectioners’ Sugar: A light dusting over the cooled bars gives them that classic bakery look and a little extra sweetness. Totally optional, but pretty for serving. If you skip it, the bars are still just as good.
Tips for Best Results
- Let them cool completely: The filling needs time to set, so don’t rush the chilling step if you want clean slices.
- Don’t skip the cornstarch: It helps thicken the berry juices so the bars hold together instead of becoming runny.
- Watch the bake time: You’re looking for bubbling edges; that’s your signal the filling has properly thickened.
- Use parchment with overhang: It makes lifting the bars out of the pan much easier and keeps the edges neat.
FAQs
Can I use frozen berries?
Yes. You can use frozen strawberries and blueberries, but don’t thaw them first. Add them straight into the filling mixture and bake as directed, adding a few extra minutes if needed.
How do I know when the bars are done baking?
The topping should be golden, and the filling should be bubbling around the edges. That bubbling is key; it means the cornstarch has activated and the filling has thickened properly.
Why do I need to chill the bars before cutting?
Chilling helps the filling fully set, which gives you clean, sturdy slices. If you cut them too soon, they’ll be softer and a bit messy (still delicious, just less neat).
Can I double this recipe?
Yes, but I recommend baking it in two 9×9-inch pans rather than one larger pan. This helps the crust and filling bake evenly without becoming too thick in the center.
How to Store Strawberry Blueberry Crumble Bars
Store leftover strawberry blueberry crumble bars in an airtight container at room temperature for up to 2 days. For longer storage, keep them in the refrigerator for up to 5 days. If refrigerated, let the bars sit at room temperature for a few minutes before serving so the crust softens slightly and the filling isn’t too firm.
These bars also freeze well. Wrap individual squares tightly in plastic wrap, then place in a freezer-safe bag or container. Freeze for up to 3 months. Thaw at room temperature before serving.
Strawberry Blueberry Crumble Bars
Ingredients
Crust
- 1 ½ cups (188 g) all-purpose flour
- ½ cup (100 g) granulated sugar
- ½ teaspoon kosher salt
- ¾ cup (1 ½ sticks / 170 g) unsalted butter, melted
Berry Filling
- 1 ½ cups (250 g) fresh strawberries, diced
- 1 ½ cups (250 g) fresh blueberries
- ¼ cup (50 g) granulated sugar
- 2 tablespoons cornstarch
- 1 teaspoon lemon zest
- 1 tablespoon fresh lemon juice
- ½ teaspoon vanilla extract
Crumble Topping
- ¾ cup (94 g) all-purpose flour
- ¼ cup (50 g) light brown sugar, packed
- ¼ teaspoon kosher salt
- 5 tablespoons unsalted butter, melted
For Serving
- Confectioners’ sugar, for dusting
- Fresh berries, for topping, optional
- Whipped topping, optional
Instructions
- Preheat oven to 350°F (175°C). Line a 9×9-inch baking dish with parchment paper, leaving overhang for easy removal. Lightly grease if needed.
Crust
- In a medium bowl, whisk together flour, sugar, and salt. Stir in melted butter until fully combined. The mixture will be crumbly but should hold together when pressed.
- Press evenly into the prepared pan.
- Bake for 12 to 15 minutes, until lightly golden. Set aside.
Berry Filling
- In a large bowl, gently toss strawberries and blueberries with sugar, cornstarch, lemon zest, lemon juice, and vanilla.
- Let sit for 5 minutes to allow juices to release and lightly thicken, then spread over the baked crust.
Crumble Topping
- In a medium bowl, whisk together flour, brown sugar, and salt.
- Stir in melted butter until crumbly clumps form.
- Sprinkle crumble topping evenly over the berry filling.
- Bake for 30 to 35 minutes, until the topping is golden and the filling is bubbling at the edges. Tent loosely with foil if the top browns too quickly.
- Transfer to a wire rack and let cool completely (about 1 hour), then refrigerate until chilled, about another hour.
- Once chilled, dust with confectioners’ sugar, then slice into bars. If desired, top with fresh berries or a dollop of whipped topping before serving.
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