In a bowl, cream butter and sugar; beat in egg and milk. Combine flour, baking powder, salt and nutmeg; stir into creamed mixture (batter will be stiff). Fill greased or paper-lined muffin cups two-thirds full. Bake at 350° for 15-20 minutes or until muffins test done. Meanwhile, melt butter and combine sugar and cinnamon. Remove muffins from oven; immediately dip tops in butter, then in cinnamon-sugar.