Instructions

1. Preheat oven to 350 degrees.
2. Place 4 tablespoons of the butter in a medium cast iron over medium low heat until the butter melts, 2 to 4 minutes. Stir the brown sugar into the melted butter in the cake pan, then, using a spatula, pat the mixture into an even layer. Lay the pineapple rounds evenly over the sugar, place one cherry in the middle of each pineapple hole.
3. Whisk the flour, baking powder, and salt together in a medium bowl. In a large bowl, beat the remaining 8 tablespoons butter and the granulated sugar together with an electric mixer on medium speed until light and fluffy, 3 to 6 minutes. Beat in the eggs and egg white, one at a time, until combined, about 30 seconds. Beat in the vanilla.
4. Reduce the mixer speed to low and beat in one-third of the flour mixture, followed by half of the milk. Repeat with half of the remaining flour mixture and the remaining milk. Beat in the remaining flour mixture until just incorporated (the batter will be thick).
5. Spoon batter over the pineapple and gently smooth the top. Gently tap the pan on the counter to settle the batter. Bake the cake until a toothpick inserted in the center comes out with a few moist crumbs attached, 45 to 50 minutes, rotating the pan halfway through baking.
6. Let the cake cool slightly in the pan, about 10 minutes. Place a serving platter over the top of the cake pan, invert the cake, and let sit until the cake releases itself from the pan (do not shake or tap the pan), about 1 minute. Gently remove the cake pan and let the cake cool completely.