Preheat the oven to 350 degrees F (175 degrees C).

Pour melted butter into the bottom of a 9x13-inch baking dish. Add peaches and 2 tablespoons sugar; toss until evenly coated.

Stir together flour, 1 cup sugar, milk, cinnamon, baking powder, and salt in a large bowl until well combined; spoon batter over peaches.

Bake in the preheated oven until the top is golden brown, about 45 minutes.