425 degree oven. Combine sugar and cinnamon in a bowl. Melt margarine in a bowl. Take one marshmallow and tightly seal it inside of one biscuit. Roll the bun in the melted margarine, covering it completely. Then roll it in the cinnamon/sugar mixture covering it completely. Place it a 9 x 13" cake pan. DO NOT use a cookie sheet; the marshmallow may leak out and run off into your oven. Repeat process until you use all of the biscuits. Bake 8 - 10 minutes. Press lightly on the buns; if they spring back they are done. These are best if served warm-hot. ENJOY!!