In a small bowl mix melted butter and brown sugar. Pour evenly into a 9-inch x 13-inch pan.
In a large mixing bowl combine cake mix, Greek yogurt, water, and coconut extract. Beat for 2 minutes.
Arrange the pineapple slices in an even layer on the bottom of the pan and push into the brown sugar mixture. Place a cherry in the center of each pineapple slice and in the holes created where four pineapples meet.
Pour cake batter on top of the fruit and spread into an even layer.
Bake for 40-45 min. Allow to cool in the pan for 5-10 minutes.
Run a knife around the edges of the pan and place a serving plate on top of the pan. Flip the cake, but leave the pan on top of the plate so that all the brown sugar can drip down.
Remove pan and sprinkle with shredded coconut or toasted coconut if desired.