Preheat your oven to 350°F (180°C).
In a mixing bowl, prepare the cake mix according to package directions, substituting the reserved pineapple juice for an equal amount of water.
In a separate bowl, mix the melted butter and brown sugar together.
Pour the butter and brown sugar mixture evenly into the bottom of a greased bundt pan.
Arrange the pineapple slices in a single layer over the butter and brown sugar mixture.
Place one cherry half in the center of each pineapple slice.
Pour the cake batter evenly over the pineapple slices.
Bake for 40-45 minutes, or until a toothpick inserted into the center of the cake comes out clean.
Remove the cake from the oven and let it cool for 5 minutes.
Invert the bundt pan onto a serving platter and let the cake cool completely.
Serve and enjoy!