Preheat the oven to 350 degrees F.
Prepare the bundt pan by generously applying pan release (recipe below) or non-stick spray.
Melt the butter and evenly pour into the bottom of the pan. Sprinkle with the brown sugar.
Cut the pineapple rings in half and alternate with the maraschino cherries around the bundt pan as shown in the picture. Set aside.
In a stand mixer or large bowl, stir the cake mix and pudding mix together. Drain the pineapple juice into a measuring cup and add enough milk to make 1 Cup of liquid. Add this with the eggs and the amount of oil called for in the recipe to the cake mixture; following the instructions on the box.
Carefully pour the batter over the fruit and bake as instructed for a bundt cake. The cake is done when an inserted knife comes out clean.
Cool for 10 minutes in the pan. Slide a knife around the edges including the inner ring.
Invert the cake onto a serving plate. Slice between the pineapple rings and serve warm or room temperature.