- 1 stick unsalted butter, softened, plus more for the baking dish
- 4 cups blackberries
- 4 cups blueberries
- 1/2 cup maple syrup
- 1/3 cup instant tapioca
- 1 1/4 cups all-purpose flour
- 1/2 cup granulated sugar
- 1/3 cup packed light brown sugar
- 1/2 teaspoon freshly grated nutmeg
- Pinch of salt
- 2/3 cup blanched hazelnuts
- 1 teaspoon vanilla extract
Preheat the oven to 375 degrees F. Butter a 9-inch-square baking dish.
Toss the blackberries and blueberries in a large bowl with the maple syrup and tapioca. Transfer to the prepared baking dish.
Combine the flour, granulated sugar, brown sugar, nutmeg and salt in a food processor and pulse to combine. Add the hazelnuts, butter and vanilla; pulse until the nuts are roughly chopped. Sprinkle the topping over the berries, pinching it with your fingers to make small clumps.
Bake until the filling is bubbling and the topping is golden brown, about 1 hour. Let cool slightly before serving.
Photograph by Kana Okada