Preheat the oven to 350 degrees F. Lightly grease a metal 9x13 metal baking pan on the sides (we like a more shallow baking pan for this recipe so inverting the cake is easier).
Drain juice from the pineapple can into a measuring cup. If it does not equal 1 cup, add water until the liquid measures 1 cup. Set aside any extra juice and the pineapple rings.
In a large mixing bowl, add cake mix, 1 cup pineapple juice, vegetable oil and egg whites. Beat until well combined and smooth (about 2 minutes).
Add melted butter to a 9x13 baking dish. Sprinkle brown sugar over the melted butter to cover it. Arrange pineapple rings in the dish without overlapping (10 - 11 rings). Place maraschino cherries into the centers of each ring and in other open spots, if desired.
Pour the cake batter over the rings and bake for 42 - 48 minutes, or until a toothpick inserted in the middle comes out clean.
Let cake cool in the pan for 10 minutes, then gently loosen the edges. Slide a sharp paring knife or a rubber spatula around the inner perimeter of the pan. Invert a serving platter larger than the cake over the top of the pan. Place one hand on the platter and one hand on the bottom of the pan, then flip. Allow the cake to sit for another few minutes with the pan still covering it, then carefully remove the pan and enjoy!