Serves 10, 1 slice per serving
1/4 C unsalted butter, divided
1/4 C packed light brown sugar
7 slices canned pineapple rings, with juice, reserve 1/4 C juice
1 C unprepared, vanilla cake mix
1 large egg
Preheat oven to 375 F degrees.
Melt 2 Tbsp butter in a 9 inch cake pan, over medium-low heat. Sprinkle sugar over top.
Place pineapple rings in a single layer.
Increase heat to medium-high. Cook until pineapple caramelizes, flipping once, about 2 minutes per side.
Remove from heat.
Melt remaining butter in microwave.
In a medium-size mixing bowl, beat egg with melted butter.
Add cake mix and reserved pineapple juice. Mix well.
Pour batter over pineapple.
Bake for 30 to 35 minutes, or until a toothpick inserted in center comes out clean.
Cool for 15 to 20 minutes, in pan. Loosen sides with a knife and invert cake onto a serving plate.
Slice into 10 pieces.