Frozen Blackberry Crisp with Cinnamon Oat Topping

Begin by preheating your oven to the optimal temperature of 375 degrees Fahrenheit, or equivalently 190 degrees Celsius.

Next, take a 1-quart baking dish and apply a thin layer of grease to prevent the crust from sticking.

To prepare the blackberry mixture, combine 1 cup of fresh or frozen blackberries, a moderate amount of granulated sugar, 2 tablespoons of cornstarch, 2 tablespoons of water, a squeeze of fresh lemon juice, and a few drops of vanilla extract in a small bowl. Gently mix the ingredients together to evenly coat the berries.

In another bowl, whisk together 1 cup of rolled oats, 1/2 cup of all-purpose flour, a generous amount of brown sugar, and a pinch of ground cinnamon. Use your fingers or a pastry blender to work in 2 tablespoons of unsalted butter until the mixture forms a crumbly texture.

Finally, sprinkle the oat mixture evenly over the blackberry mixture in the prepared baking dish. Bake, uncovered, in the preheated oven for 20 to 25 minutes, or until the filling is bubbly and the crust is golden brown.