This Mixed Berry Crisp combines juicy strawberries, blueberries, raspberries, and blackberries with a buttery oat topping. An easy, family-friendly dessert that’s perfect for summer and ready in under an hour.
Preheat oven to 375°F (190°C) and lightly grease an 8x8 or 9x9-inch baking dish.
In a large bowl, gently toss together the berries, granulated sugar, cornstarch, lemon juice, salt, and cinnamon. Mix until the berries are evenly coated and beginning to release their juices. Transfer the mixture to the prepared baking dish.
In a separate bowl, combine the oats, flour, brown sugar, cinnamon, and salt. Add the cold butter cubes and use your fingers or a pastry cutter to work the butter into the mixture until pea-sized crumbs form. For an extra crunchy topping, chill the mixture for 15 minutes before baking.
Evenly sprinkle the oat topping over the berry mixture, leaving some clumps for texture. Bake for 35–45 minutes, until the topping is golden brown and the berry filling is bubbling around the edges. If using frozen berries, add 3–5 extra minutes of baking time.
Allow the crisp to cool for 10–15 minutes so the filling thickens. Serve warm with ice cream or whipped cream.