Preheat the oven to 350°F (175°C).

In a small bowl, mix the melted butter and brown sugar until well combined.

Pour the mixture into the bottom of the cake pan.

Arrange the pineapple slices on top of the sugar mixture and place a cherry in the center of each slice if desired.

In a mixing bowl, whisk together the flour, granulated sugar, baking powder, baking soda, and salt.

In another bowl, combine the milk, vegetable oil, egg, and vanilla extract.

Add the wet ingredients to the dry ingredients and mix until just combined.

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

Bake in the preheated oven for 35-40 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool for 10 minutes, then invert onto a serving plate.