Crumb Topping: 1/2 cup sugar 3/4 cup self-rising flour 1 teaspoon cinnamon 1/4 cup butter, softened
Buckle: 1-1/2 cups self-rising flour 3/4 cup sugar 1 egg 1/2 cup milk 1/4 cup butter, melted 1 teaspoon vanilla 2 cups fresh or frozen blueberries
Heat the oven to 375 degrees. Grease a 9-inch cast iron skillet or 11 x 7-inch baking dish. For the crumb topping: Combine the sugar, flour, and cinnamon in a small bowl. Rub the butter into the flour with your fingers until crumbly. Set aside.
To make the buckle: Combine the flour and sugar in a medium mixing bowl. In a small bowl, whisk together the egg, milk, butter and vanilla. Pour the liquid over the flour mixture and stir with a fork just until the flour is moistened and a lumpy batter forms. Pour the batter into the greased skillet. Scatter the blueberries over the top. Sprinkle with the crumb topping. Bake 40 to 45 minutes or until golden brown. Serve warm.