Melt the butter over medium-low heat in a 10” cast iron skillet. Remove from heat and spread the brown sugar evenly over the bottom of the skillet.
Drain the pineapple reserving 1/4 cup of the juice. Arrange pineapple slices in a single layer on top of the brown sugar. Place a maraschino cherry in the center of each slice.
Beat the egg yolks in a medium bowl until light yellow and thickened. Gradually beat in the sugar. Gradually add the reserved juice to the yolk mixture, beating well.
With the mixer on slow speed, slowly add the flour, salt, and baking powder to the egg yolk mixture, until blended.
In a separate bowl, beat the egg whites until stiff peaks form. Fold the egg whites into the egg yolk and flour mixture. Spoon batter over pineapple slices.
Bake for 40-50 minutes or until a skewer inserted near the center comes out clean. Cool cake in skillet for 30 minutes. Invert onto a serving plate.
May be served warm or cold with whipped cream or ice cream if desired.
Storage:This dessert can be left out at room temperature for at least 24 hours. After that, it’s best stored in the refrigerator. It’s easiest to wrap the cake and serving plate together in plastic wrap. then store it in the refrigerator for up to three days. To freeze – allow the cake to cool completely. Wrap tightly in plastic wrap followed by aluminum foil. Place the wrapped cake in a zip top bag and freeze for up to three months. To serve, allow the cake to thaw overnight in the refrigerator. It can be rewarmed in a low oven.
To remove the cake from the pan, first let it cool on a wire rack for 15 to 30 minutes. After cooling, run a knife or spatula between the cake and pan. Then, using a serving plate that is larger all around than the pan, place the plate upside down on top of the pan. Grasp the pan and plate with both hands and invert the whole thing (be sure to use oven mitts if the pan is still hot). Sit the plate down and carefully lift the pan.
If you don’t have a cast iron skillet, you can easily substitute a standard 9-inch cake pan or square baking pan.