Preheat oven to 180°C (350°F).
Pour melted butter into cake pan and sprinkle with brown sugar.
Arrange pineapple slices over sugar and add cherries in the center.
In a bowl, whisk flour, baking powder, and salt.
In another bowl, beat eggs and sugar, then add milk, oil, and vanilla.
Gradually mix dry ingredients into wet ingredients until combined.
Pour batter over pineapple layer and spread evenly.
Bake for 35–40 minutes or until a toothpick comes out clean.
Cool 10 minutes, then confidently flip onto a serving plate.