Melt the butter and blend with the brown sugar, smooth into the bottom of a 9x13" baking dish, lightly sprayed with Pam. Arrange pineapple rings onto bottom of pan. Place a cherry in the center of the ring. Sprinkle with the pecans. Smooth the crushed pineapple over all. Make cake according to box. Spread batter over pineapple mixture. Bake at 350 for 40-60 minutes. Oven temperatures vary. Use pick test. When done immediately invert onto plate. Serve with whipped cream. I add a little cinnamon to my whipped cream if the mood hits me. If it looks like it's browning too much, lower temp to 325. Using dark or glass pans can vary baking times as well.