Preheat oven to 350°F (175°C).

In a 9-inch round cake pan, melt the butter in the oven. Sprinkle the brown sugar evenly over the melted butter. Arrange the drained pineapple slices on top of the brown sugar. Place a maraschino cherry in the center of each pineapple slice.

In a large bowl, cream together the granulated sugar and shortening until light and fluffy. Beat in the egg and vanilla extract until well combined.

Gradually add the milk to the creamed mixture, beating until just combined.

In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.

Pour the cake batter evenly over the pineapple layer in the cake pan.

Bake for 50-55 minutes, or until a toothpick inserted into the center of the cake comes out clean.

Immediately after removing the cake from the oven, place a heatproof serving plate upside down over the cake pan. Carefully and quickly invert the pan and plate together. Let the pan sit for a few minutes to allow the topping to release, then lift the pan off.

Let the cake cool for about 15 minutes before serving warm.