Preheat oven to 350°F (175°C). Generously spray a 12-cup muffin tin with non-stick baking spray.
Mix melted butter and brown sugar. Press evenly into the bottom of each muffin cup.
Arrange dried pineapple pieces and a cherry half on top of the brown sugar mixture in each cup.
In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
In a stand mixer, cream the softened butter and granulated sugar until light and fluffy (about 3 minutes).
Beat in the eggs one at a time, followed by the vanilla extract.
Alternate adding the dry ingredients with the milk and pineapple juice, beginning and ending with the dry ingredients. Mix until just combined.
Divide the batter evenly into the muffin cups over the fruit. Bake for 20-25 minutes until a toothpick comes out clean.
Let cool in the pan for exactly 5 minutes, then place a cutting board over the pan and confidently invert to release the cakes. Serve warm.