Preheat oven to 350 degrees F.
Melt 4 tablespoons butter in a 10-inch cast iron skillet or 9-inch round cake pan over medium heat. Remove from heat. Sprinkle brown sugar evenly over the butter and stir into a rough paste.
Pat drained pineapple slices dry. Arrange over brown sugar: one ring in center, remaining rings around it. Press firmly. Place a maraschino cherry in each ring center and in gaps between slices.
Whisk flour, baking powder, baking soda, and salt in a bowl. Set aside.
Beat butter and granulated sugar on medium-high for 3 minutes until pale and fluffy. Add eggs one at a time, scraping bowl between each. Add vanilla. Mix in sour cream on low.
Add flour mixture in two additions, alternating with pineapple juice. Mix on low. Stop as soon as incorporated.
Pour batter gently over the fruit from the center outward. Spread carefully without disturbing the fruit.
Bake 38 to 45 minutes until cake tester comes out clean and edges are golden.
Rest in pan 5 to 10 minutes. Place large heatproof plate firmly over pan. Flip in one confident motion. Hold 5 seconds. Lift pan away slowly. Spoon any dripped caramel back over the cake.
Serve warm or at room temperature. Dust with powdered sugar if desired.