- 3 cups fresh blackberries
- 2 tablespoons white sugar
- 1 teaspoon vanilla extract
- Batter:
- 1 1/4 cups all-purpose flour
- 3/4 cup white sugar
- 1/2 cup almond meal
- 2 teaspoons baking powder
- 1/4 teaspoon salt
- 1 pinch ground cinnamon
- 1 cup milk
- 7 tablespoons butter, divided
- 3 tablespoons sliced almonds, or to taste
- Preheat oven to 350 degrees F (175 degrees C).
- Stir blackberries, 2 tablespoons sugar, and vanilla extract together in a bowl; let rest, 15 to 20 minutes.
- Whisk flour, 3/4 cup sugar, almond meal, baking powder, salt, and cinnamon together in a bowl. Stir milk into flour mixture until batter is just combined.
- Melt 6 tablespoons butter in a skillet over medium-high heat; pour into the bottom of a 8×12-inch baking dish. Pour batter over melted butter into the baking dish, using a spatula to gently distribute batter without mixing it into the butter, leaving a 1-inch butter border around the sides of the dish.
- Scatter blackberries over the batter and spoon any accumulated blackberry juices over the top.
- Bake buckle in the preheated oven until crisped and browned around the edges, about 1 hour.
- Melt remaining butter in a small skillet over medium-high heat. Cook and stir almonds in hot butter until golden brown and toasted, 2 to 3 minutes. Sprinkle toasted almonds over blackberry buckle and cool buckle to room temperature.