Preheat the oven to 350°F (175°C).

In a mixing bowl, combine melted butter and brown sugar until smooth.

Pour the mixture into the bottom of the cake pan.

Arrange the pineapple slices over the sugar mixture and place a cherry in the center of each slice if using.

In another bowl, whisk together flour, sugar, baking powder, and salt.

In a separate bowl, mix milk, vegetable oil, vanilla extract, and egg until well combined.

Gradually add the wet ingredients to the dry ingredients, stirring until just combined.

Pour the cake batter over the pineapple topping in the pan.

Bake in the preheated oven for 40-45 minutes or until a toothpick inserted in the center comes out clean.

Allow to cool for 10 minutes, then invert onto a serving plate.