1. Preheat the oven to 350 degrees F.
2. For the wet ingredients: In a large mixing bowl, add and combine together the butter, condensed milk, milk and vanilla extract using an electric mixer. Make sure the mixture is smooth.
3. For the dry ingredients: In a medium sized bowl, add and combine together the plain flour, baking soda and baking powder using a spoon.
4. Take the bowl of dry ingredients and slowly add it into the wet ingredients bowl about 1/2 cup measurement at a time. First mix it well with the electric mixer and beat it at a slow speed until well combined. Repeat this step, until all the dry ingredients have been folded into the wet ingredients.
5. Take a 9 inch spring form pan and coat the bottom with 2 tablespoon of melted butter and sprinkle it some dry flour.
6. Once done, take the pineapple slices and place them inside the spring form pan (adjusting the slices as required), take 3-4 cherries and place them inside the holes of the pineapple slices.
7. Once done, take the cake batter and pour it evenly onto the pineapple slices making sure they are completely covered.
8. Bake this in the preheated oven at 350 degrees F for 25 - 30 minutes or until a tooth pick inserted in the center of the cake comes out clean.
9. After 30 minutes, remove the cake from the oven and let it sit for about 10 minutes before releasing the spring pan.
10. After 10 minutes, release the spring pan and place the cake upside down onto a cooling rack to cool completely before slicing it.
11. Serve a slice of this upside down pineapple cake on a dessert plate with a scoop of vanilla ice cream.