Best Blueberry Buckle

2 cups all-purpose flour

2 teaspoons baking powder

½ teaspoon salt

¼ cup unsalted butter

¾ cup white sugar

1 large egg

½ cup milk

2 ½ cups fresh blueberries

½ cup white sugar

⅓ cup all-purpose flour

½ teaspoon ground cinnamon

¼ cup unsalted butter, softened

Preheat oven to 350 degrees F (175 degrees C). Butter and flour a springform pan.

Sift 2 cups flour, baking powder, and salt into a bowl.

Beat 1/4 cup butter, 3/4 cup sugar, and egg with an electric mixer in a large bowl until smooth. Gradually add milk and beat until fluffy; stir in flour mixture, making a stiff batter. Gently fold in blueberries and spread batter into prepared springform pan.

Mix 1/2 cup sugar, 1/3 cup flour, cinnamon, and 1/4 cup butter in a bowl until blended and crumbly in texture. Sprinkle on top of batter, then lightly press topping into batter using fingertips.

Bake in preheated oven until golden and a toothpick inserted in the middle comes out with moist crumbs, about 40 minutes.