Preheat your oven to 350°F. Grease or spray an 8-inch or 9-inch casserole or baking dish.
Place the blueberries, peaches, brown sugar, cornstarch, and cinnamon in a large mixing bowl. Stir together to combine & coat the fruit evenly.
Pour the fruit filling into your prepared baking dish. Spread evenly and set aside.
To make the crisp topping, place the oats, flour, sugar, cinnamon, and salt in a bowl. Stir to combine.
Pour the melted butter over the oatmeal mixture in the bowl and stir until thoroughly incorporated.
Spoon the topping over the blueberry peach filling and gently spread until the filling is covered evenly.
Bake for 45-55 minutes or until the crisp topping is lightly browned and the filling is bubbly and warm.
Serve warm, as is, or top with whipped cream or vanilla ice cream and enjoy
Store your peach blueberry crisp for 2-3 days at room temperature or 3-4 days refrigerated. Be sure to cover with plastic wrap or aluminum foil or store in an airtight container.Other fruits that would pair well with the flavors in this recipe: blackberries, raspberries, strawberries, apples