Preheat oven to 350˚ F.
Pour melted butter into the bottom of a 10-inch deep-dish cake pan and sprinkle 1/2 cup brown sugar evenly over top.
Arrange the pineapple slices on top of the butter mixture and up the sides, if desired. Set aside.
In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
In a large bowl, beat the remaining brown sugar and butter together until smooth. While stirring, slowly add the milk, vanilla, egg, and pineapple juice until combined.
Add the dry ingredients to the wet mixture and beat until combined with no lumps.
Pour the batter over the pineapple and spread evenly — some of the fruit may poke through the batter.
Bake for 45 minutes or until golden brown and the top springs back when pressed with your finger.
Allow the cake to cool in the pan for 5 minutes then flip it onto a plate or platter and leave the pan on the cake for 10 minutes longer.
Carefully remove the cake pan and allow the cake to cool to room temperature.
Top with cherries and whipped cream before serving.