Cherry Berry Crumble is an especially wonderful dessert for the transition from summer to fall! May be served either warm or at room temperature. Good with a scoop of vanilla ice cream, or dollop of fresh whipped cream. Adapted from Martha Stewart.
Preheat oven to 375 degrees, with a rack in the lower third. Butter a 3-quart baking dish, and place on a parchment-lined baking sheet; set aside.
Make Topping: In a large bowl, whisk together flour, brown sugar, 1/3 cup granulated sugar, cinnamon, mace, and 1/4 teaspoon salt. Using a pastry blender, cut in butter until large clumps form. Using a rubber spatula, mix in oats. Set aside.
Make Filling: In a large bowl toss together berries, cherries, lemon juice, vanilla extract, 1/2 cup brown sugar, 2 tablespoons flour, and 1/4 teaspoon salt to combine.
Pour the cherry and berry mixture into the prepared baking dish; sprinkle with reserved oat mixture, covering fruit evenly.
Bake until juices are bubbling and the topping is evenly browned, about 50 minutes. Cool slightly on a wire rack. Serve crumble warm or at room temperature, topped with vanilla ice cream or whipped cream, as desired.