Nonstick cooking spray
3 cups cake flour, plus more for pan
1 cup butter, softened, plus 1/2 cup, melted
2 1/4 cups sugar
5 large eggs
1 teaspoon vanilla extract
2 teaspoons baking powder
1/4 teaspoon salt
1 1/4 cups whole buttermilk
1 1/2 cups firmly packed brown sugar
2 (20-ounce) cans pineapple slices in juice, drained well (reserve 2 tablespoons juice for frosting)
1 (10-ounce) jar maraschino cherries, drained well
Pineapple Buttercream Frosting, recipe follows
Chopped pecans, for garnish, optional
1/2 cup butter, softened
2 tablespoons reserved pineapple juice
3 1/2 cups confectioners' sugar