In a small saucepan, melt 0.25 cup butter over low heat. Stir in the brown sugar and mix until well combined. Pour the mixture into a 9-inch round cake pan, spreading evenly.
Place pineapple slices over the brown sugar mixture and place a cherry in the center of each slice.
In a medium bowl, whisk together flour, baking powder, and salt.
In a large bowl, beat the 1.5 cup sugar and melted butter until fluffy. Beat in eggs one at a time, then stir in the vanilla. Mix in the flour mixture alternately with the milk. Pour batter over the pineapple layer.
Bake for 45 minutes or until a toothpick inserted into the center comes out clean. Cool in the pan 10 minutes before inverting onto a serving plate.
Notes
This cake is best served warm, with a scoop of vanilla ice cream for an extra touch of indulgence.