1Heat oven to 350°F. Add melted butter to 12-inch cast iron or ovenproof skillet. Sprinkle brown sugar evenly over butter. Arrange 8 pineapple slices in bottom of skillet. Cut remaining slices in half; arrange around inside edge of skillet. Place 1 cherry in center of each whole and half pineapple slice.
2In large bowl, beat cake mix, pineapple juice, oil and eggs with electric mixer on low speed until moistened; beat 2 minutes on high speed. Pour into skillet over fruit.
3Bake 40 to 45 minutes or until cake is golden brown and springs back when touched lightly in center.
4Cool cake in skillet 5 to 10 minutes. Run knife around edge of cake to loosen. Place heatproof plate upside down over skillet; turn plate and skillet over. Remove skillet. Serve cake warm.