Pineapple Upside-Down Cakes
- 1 tablespoon unsalted butter
- 1 cinnamon stick, broken in half
- 1 large pineapple, peeled, cut into eight 1/2' rounds, cored
- 1/4 cup (packed) dark brown sugar
- 2 tablespoons unsalted butter, melted
- 1/2 teaspoon vanilla extract
- Nonstick vegetable oil spray
Melt butter with cinnamon stick in a large heavy skillet over medium heat. Cook until butter begins to brown, about 2 minutes. Add pineapple slices; cook until light golden brown, 4–5 minutes per side. Remove skillet from heat; add rum and brown sugar. Cook over medium-high heat until juices are thick and syrupy. Transfer pineapple to a plate; let cool. Reserve syrup.
Preheat oven to 325°. Set a wire rack on a rimmed baking sheet. Whisk first 4 ingredients in a large bowl. Add buttermilk and next 3 ingredients; whisk until smooth.
Heat a griddle or large heavy skillet over medium heat. Lightly coat with nonstick spray. Working in batches, pour batter by 1/4-cupfuls onto griddle. Cook each pan- cake until golden brown and bubbles form on top, about 2 minutes. Top each pancake with a pineapple ring. Flip; cook until pancake is golden brown, about 2 minutes. Place pancakes on prepared rack and bake in oven until cooked through, about 5 minutes.
Rewarm reserved pineapple syrup. Divide pancakes among plates; drizzle with pineapple syrup.