Position the rack in the upper-middle of the oven. Preheat the oven to 350 degrees F (175 degrees C).
Put butter in an 8-inch square or 9-inch round pan; melt in the oven. Remove from the oven and set aside.
Whisk flour, 3/4 cup sugar, baking powder, and salt in a medium bowl. Whisk in milk until a smooth batter forms.
Pour batter into the prepared pan.
Scatter fruit over batter. Sprinkle with 1 tablespoon sugar.
Bake in the preheated oven until top is light brown, and fruit bubbles, 50 to 60 minutes.
Serve warm or at room temperature.