In a mixing bowl, cream shortening, sugar and egg. Combine dry ingredients; ad d to creamed mixture alternately with milk. Fill greased muffin tins 2/3 full. Bake at 325 degrees for 20-25 minutes or until golden. Let cool for 3-4 minu tes. Meanwhile, combine sugar and cinnamon in a small bowl. Roll warm muffins in melted butter, then in sugar mixture. Serve warm.