Preheat your oven to 350°F. Spray a 9-inch cake pan that is at least 2 inches deep with nonstick cooking spray. Line the bottom with parchment paper.
Cut 3 pineapple slices in half. In the bottom of the cake pan, pour the 4 Tablespoons of melted butter, tilting to coat the bottom. Sprinkle evenly with the ⅓ cup of brown sugar. Arrange the whole **pineapple slices** over the brown sugar and place the halved slices upright evenly around the sides of the pan. Add 1 cherry to the center of each pineapple slice.
In a small bowl, stir the 1 ½ cups of flour, 1 ½ teaspoons of baking powder, and ¼ teaspoons of salt until combined.
In a large bowl, whisk together the 6 Tablespoons of butter, ¾ cup granulated sugar, and ¼ cup brown sugar until well combined. Whisk in 2 large eggs and 1 ½ teaspoons of vanilla until smooth.
Mix in 1/3 of the flour mixture, followed by 1/3 cup of the buttermilk. Repeat until all ingredients are combined. Pour the batter over the top of the pineapples.
Bake for 45 to 50 minutes, or until golden brown and a toothpick inserted in the center comes out clean. Tent the cake with foil halfway through bake time to prevent the top from getting too brown.
Let cool for at least 10 minutes in the pan. Run a knife around the edges of the cake to loosen it from the pan. Place a serving platter over the top of the cake and carefully flip it upside down. Remove the parchment and let cool completely.
