Preheat oven to 350 degrees F (175 degrees C). Pour butter into 9-inch round baking pan.
Mix 1 cup sugar, flour, and baking powder together in a bowl. Stir in milk. Pour batter into the baking pan.
Arrange apples over the batter; sprinkle remaining 1/4 cup sugar and cinnamon on top. Pour in water.
Bake in the preheated oven until golden brown, about 45 minutes.