Preheat oven to 350°F (175°C).

In a 9-10 inch cast iron skillet (or cake pan), melt butter over low heat. Stir in brown sugar until dissolved.

Arrange pineapple rings in the skillet and place a maraschino cherry in the center of each ring.

In a bowl, beat egg yolks until light, then mix in sugar, 1/2 cup pineapple juice, and vanilla extract.

In a separate bowl, sift together flour, baking powder, and salt. Stir into the wet mixture until combined.

In another bowl, beat egg whites until stiff peaks form. Gently fold into the batter.

Pour the batter over the pineapples in the skillet.

Bake for 35-45 minutes, or until a toothpick inserted in the center comes out with just a few crumbs.

Let the cake cool for 10 minutes, then place a serving plate over the skillet and invert the cake onto the plate.

Serve warm and enjoy!