Mixed Berry Crumble Bars That Look Like a Bakery Window
These mixed berry crumble bars come together in 15 minutes of active work and look like they cost $6 a slice. Frozen berries give a perfect jammy center, and a food processor makes the buttery oat crust effortless. Nine ingredients, one pan, and they slice cleanly.
Equipment
- 9x13 Baking Dish
- Food Processor
- Parchment Paper
- Skillet or saucepan
- Wire Rack
Ingredients
For the Crust and Streusel
- 2 1/2 cups all-purpose flour
- 1 cup granulated sugar
- 1 pinch kosher salt
- 1 cup unsalted butter, cold and cubed
- 1 1/2 cups old-fashioned rolled oats
For the Berry Filling
- 3 cups frozen mixed berries
- 1/2 cup granulated sugar
- 2 tablespoons lemon juice
- 3 tablespoons cornstarch
Instructions
- Preheat oven to 375°F. Line a 9x13 baking dish with parchment paper, leaving overhang on the two long sides.
- Make the crust and streusel: In a food processor, combine flour, 1 cup sugar, and salt. Pulse to combine. Add cold cubed butter and pulse until shaggy (about 10 pulses). Add oats and pulse twice more. Set aside 1 1/2 cups for the topping.
- Press the remaining crust mixture firmly into the prepared dish. Bake for 15 minutes, until just golden at edges.
- Meanwhile, in a skillet over medium heat, combine frozen berries, 1/2 cup sugar, lemon juice, and cornstarch. Cook, stirring occasionally, until berries thaw and mixture thickens (5-7 minutes). It should look like loose jam.
- Pour the berry filling over the hot crust and spread evenly. Sprinkle the reserved crumble mixture on top, squeezing some into clumps for crunchy bits.
- Bake for 35-40 minutes, until deeply golden and bubbling at edges. Cool completely in the pan on a wire rack (about 2 hours). Use parchment to lift out, then slice into 16 bars with a sharp knife.
Notes
Press the crust firmly — a flat measuring cup works great. Don't overwork the streusel; two pulses after adding oats is enough. Let the filling thicken on the stove for the full 5-7 minutes. Cooling completely is essential for clean slices. Store in an airtight container at room temp for 2 days, fridge for 5 days, or freeze individual bars wrapped in parchment for up to 3 months. For a gluten-free version, use a 1:1 gluten-free flour blend and certified GF oats. For dairy-free, use cold vegan butter sticks (like Miyoko's).