Preheat the oven to 375 degrees F (190 degrees C).
Mix blueberries, orange juice, and 3 tablespoons sugar in an 8-inch square baking dish.
Mix flour, baking powder, and salt in a small bowl.
Cream butter and 1 cup sugar in a large bowl until light and fluffy. Beat in egg and vanilla. Gradually add flour mixture, stirring just until ingredients are combined.
Drop spoonfuls of batter over the blueberry mixture, covering as much filling as possible.
Bake in the preheated oven until topping is golden brown and filling bubbles, 35 to 40 minutes.