Ingredients
1/4 cup/30 grams all-purpose flour
3 tablespoons old-fashioned oats or finely chopped toasted nuts
2 tablespoons brown sugar, preferably dark
Salt
3 tablespoons cold unsalted butter, cut into cubes
2 cups fresh or frozen mixed blueberries, raspberries and blackberries (or just blueberries; no need to thaw)
1 tablespoon brown sugar, preferably dark, plus more as needed
1 teaspoon lemon or lime juice, or white distilled vinegar
Salt
Heavy cream or vanilla ice cream, for serving (optional)
Directions
1
Make the topping: In a microwave-safe shallow bowl or plate, use your hands to stir together the flour, oats, sugar and a pinch of salt until combined. Add the butter and use your fingers to rub the butter into the flour mixture until all the flour is absorbed and the mixture holds together in clumps when squeezed. Break the mixture up into small clumps. Microwave, stirring gently every 30 seconds, until dry and a shade darker, 2 to 3 minutes. Don’t worry if the mixture seems loose; it will form small clumps after stirring. Set aside to cool and crisp.
2
Cook the fruit: While the topping cools, in a small or medium skillet over medium heat, stir together 1 1/2 cups berries, the brown sugar, 2 tablespoons water, lemon juice and a pinch of salt. Cook, stirring and mashing often, until thick and jammy, 4 to 7 minutes. Add the remaining berries and stir until the berries are warm, 1 to 2 minutes. Taste and add more sugar if necessary.
3
Sprinkle the fruit with the topping. Eat portions with a pour of cream or scoop of ice cream, if desired.