- 6 tablespoons unsalted butter, at room temperature, plus more for the baking dish
- 1 1/2 pound (about 5 cups) organic mixed berries, such as hulled and chopped strawberries, blackberries, blueberries and/or raspberries
- 1/3 cup plus 1/4 cup dark brown sugar, divided
- 3/4 cup all-purpose flour, divided
- 1 cup old-fashioned or quick-cooking oats
Preheat the oven to 375°F. Lightly butter an 8- or 9-inch-square baking dish or 9-inch pie plate.
In a large bowl, combine fruit, 1/3 cup sugar and 1/4 cup flour and toss until evenly coated. Transfer to the buttered baking dish.
To make topping, stir together oats, remaining 1/4 cup sugar and 1/2 cup flour. Using a pastry blender or 2 knives, cut butter into oat mixture until well-combined. Spread topping over fruit, pressing down slightly.
Bake until the top is golden brown and the fruit is tender and bubbly, about 40 minutes. Let cool 10 minutes and serve warm.