Make Topping

1. Melt the butter in the cast iron skillet over low heat. Add both brown sugars and stir until all the lumps are gone
2. Turn up the heat to medium-high and cook, 2 minutes Tilt the pan back and forth to avoid burning and ensure even cooking
3. Place the whole pineapple rings in the pan. Slice the remaining rings in half and position around the sides of the pan and add the maraschino cherries to centers of the rings
4. Remove from heat and set aside

Make Cake

1. Place a rack in the lower 3rd of the oven and preheat to 375°
2. Sift flour baking soda, baking powder and salt together in a small bowl 
3. In a standing mixer with the paddle attached, cream together the butter and ¾ cup of sugar on medium speed until light and fluffy
4. Add the egg yolks and vanilla to the butter mixture and beat until smooth, scraping down the sides at least once 30. Set aside
5. In a clean bowl, beat egg whites until foamy
6. Start to gradually add remaining ¼ cup of sugar and beat until whites are at soft peaks. Set aside
7. With the mixer on low speed add half the dry ingredients to the butter mixture and blend until just incorporated
8. Add half of the buttermilk and mix on low speed for about 8 seconds. Add remaining flour, then remaining buttermilk. Mix until almost combined
9. Remove bowl from stand mixer and finish mixing by hand with a rubber spatula
10. Fold in one-third of the whites into the batter (to loosen the mixture), then fold in the remaining egg whites

Assemble Cake & Bake

1. Pour the batter over the pineapple and gently spread to distribute. Place the skillet on the sheet pan in the oven and bake until cake is golden and springs back to the touch. A tester inserted into the cake should come out clean, about 30-40 minutes
2. Let the cake sit for a few minutes, then run an offset spatula around the sides
3. Invert onto a plate that is slightly larger than the skillet, while the cake is still warm (use oven mitts!)
4. Slice and serve warm, or at room temperature

Recipe adapted from The Rosie's Bakery All-Butter, Cream-Filled, Sugar-Packed Baking Book by Judy Rosenberg, copyright © 2011 by Workman Publishing Company