Make the biscuit mix and use it as a base for this fruit-filled dessert casserole, which has a sweet and crispy topping.
Heat oven to 350°F. Grease the bottom and 1/2-inch up the sides of a 1-1/2- to 2-quart baking dish. In a medium bowl, combine biscuit mix, 1/2 cup sugar, the egg, milk, and lemon peel. Stir until moistened.
Spoon batter into pan. Top with fruit. Mix flour and remaining sugar in a bowl. Using a fork, cut in butter until mixture is crumbly; sprinkle over fruit. Bake for 50 to 60 minutes, or until a toothpick inserted into center comes out clean. Let cool for half an hour. Serve warm.