Pour the melted butter into a cake pan or skillet.
Sprinkle the brown sugar over the melted butter and then top with the pineapple rings, placing maraschino cherries in the centers of the rings and in the open spaces.
Preheat the oven to 350°F.
In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
Using a stand mixer, or a hand mixer with a large bowl, cream the sugar with the unsalted butter, mixing on medium until slightly fluffy and pale in color, about 3 to 4 minutes. Scrape down the sides of the bowl a couple of times.
Whisk in the eggs, pineapple juice, and vanilla extract.
With the mixer running, add half of the flour mixture, once incorporated, add half of the milk. Once incorporated, repeat with remaining flour and then milk. Mix until fully combined; the batter will be somewhat thick.
Use a spatula to help pour the batter into the prepared pan and gently spread over the pineapples and cherries.
Bake for 45 minutes, or until a toothpick comes out clean when stuck into the center of the cake.
Let rest for 10 minutes, and then invert the cake onto a cake stand or serving plate.
Slice and serve warm or at room temperature. Great with ice cream or whipped cream.
