Preheat oven to 350°F (175°C).
In a 9-inch round cake pan, melt ¼ cup butter and sprinkle brown sugar evenly.
Arrange pineapple rings on top and place cherries in the centers.
In a bowl, whisk flour, baking powder, and salt.
In another bowl, beat ½ cup butter + granulated sugar until fluffy.
Alternate adding dry ingredients and milk, mixing until smooth.
Pour batter over the pineapple layer, spreading evenly.
Bake for 35-40 minutes or until a toothpick comes out clean.
Let cool 10 minutes, then invert onto a plate.
Serve warm or at room temperature.