Preheat your oven to 350°F (175°C).
In the 9-inch round cake pan, add the softened butter and brown sugar. Use a spoon to stir until well combined. Spread it evenly across the bottom of the pan.
Arrange the drained pineapple slices on top of the brown sugar mixture, placing cherries in the centers of the pineapple rings for decoration.
In a mixing bowl, whisk together the flour, granulated sugar, baking powder, baking soda, and salt until well mixed.
In another bowl, combine the milk, eggs, and vanilla extract. Whisk until well blended.
Slowly pour the wet ingredients into the dry ingredients and mix until just combined. Be careful not to overmix; the batter should be slightly lumpy.
Gently pour the batter over the pineapple and cherries in the cake pan, spreading it evenly using a rubber spatula.
Bake in the preheated oven for 40 minutes or until a toothpick inserted into the center comes out clean.
Remove the cake from the oven and let it cool in the pan for about 10 minutes. Then, carefully invert the cake onto a serving plate to reveal the pineapple topping.
For an extra touch, you can serve the cake warm with a scoop of vanilla ice cream.