Spray baking dish with Pam. Drain liquids from pineapple and sweet potatoes. Reserve 2 slices of pineapple for top. Slice up sweet potatoes. Line sides of 8"x8" baking dish or 3 quart casserole dish with pineapple and pour sweet potatoes into dish. Sprinkle cinnamon and mace over sweet potatoes. Pat with butter. Put extra slices of pineapple on top. Pour maple syrup over mixture. Bake for about 30 minutes at 325 degrees.
Put a layer of miniature marshmallows over top of hot mixture. Place back in oven and bake until top of marshmallows has turned golden brown. This casserole can also be prepared in a microwave oven except for the browning of the marshmallows. Check your microwave directions for cooking time. to brown the marshmallows, heat oven to 425 degrees and cook for approximately 8 to 10 minutes, or until marshmallows are toasty or golden brown.
