6 cups mixed berries – rinsed and well-drained (blueberries, raspberries, blackberries, strawberries hulled and halved)
0.5 cups granulated sugar
3 tbsp cornstarch
2 tbsp lemon juice – freshly squeezed
1 cups all-purpose flour
0.5 cups light brown sugar
0.25 tsp fine salt
8 tbsp unsalted butter – cold, cut into small cubes
vanilla ice cream – for serving (optional)
Instructions
Heat the oven to 375°F (190°C) with a rack in the center.
In a large bowl, combine the mixed berries, granulated sugar, cornstarch, and lemon juice. Toss gently to coat, then spread the fruit evenly in a 2-quart baking dish (about 8-inch square or 9-inch round).
In a medium bowl, whisk the flour, light brown sugar, and salt. Add the cold butter cubes and rub them into the dry ingredients with your fingertips (or use a pastry cutter) until the mixture forms moist clumps with some pea-sized bits.
Scatter the crumble evenly over the fruit, leaving small gaps for steam to escape.
Bake until the topping is deep golden and the berry juices are bubbling thickly around the edges, 40–45 minutes. If the top browns too quickly, tent loosely with foil for the last 10 minutes.
Let the crumble cool 15–20 minutes so the juices set slightly. Serve warm, with vanilla ice cream if desired.