Preparation Preheat oven to 425°F with rack in middle. Stir together fruits, 1/2 cup sugar, cornstarch, and vanilla and place in a buttered shallow 2-quart baking dish. Stir together oats, flour, salt, and remaining 1/2 cup sugar. Blend in butter with your fingertips until mixture forms small clumps. Scatter over fruit and bake until juices are bubbling and topping is golden brown, about 20 minutes. Cool slightly before serving.
Preparation Preheat oven to 425°F with rack in middle. Stir together fruits, 1/2 cup sugar, cornstarch, and vanilla and place in a buttered shallow 2-quart baking dish. Stir together oats, flour, salt, and remaining 1/2 cup sugar. Blend in butter with your fingertips until mixture forms small clumps. Scatter over fruit and bake until juices are bubbling and topping is golden brown, about 20 minutes. Cool slightly before serving.