01 - Preheat the oven to 350°F. Lightly grease an 8x8 inch baking dish.
02 - In a large bowl, mix orange and lemon segments with granulated sugar, cornstarch, vanilla extract, and citrus zest until the fruit is evenly coated. Transfer this mixture to the prepared baking dish.
03 - In a separate bowl, combine rolled oats, all-purpose flour, brown sugar, salt, and cinnamon. Stir in melted butter until the texture resembles coarse crumbs.
04 - Evenly sprinkle the crisp topping over the citrus filling. Bake for 35 minutes or until the topping is golden brown and the filling is bubbling.
05 - Allow to cool at least 10 minutes before serving. Enjoy warm or chilled.