Preheat oven to 375 degrees F (190 degrees C).

In a small baking dish, combine butter, sugar, flour, baking powder, salt, and milk until smooth.

In a microwave-safe bowl, combine apples and cinnamon. Microwave until apples are soft, 2 to 5 minutes. Pour apples into the center of the batter.

Bake in the preheated oven 30 minutes, or until golden.