Combine butter and sugar: cream until light and fluffy. Add eggs and sour cream, mixing well. Combine flour, baking powder, baking soda, salt and nutmeg in a separate bowl. Mix well then add to batter and combine completely.
Pour batter into a greased 9 x 13 x 2 inch pan. Combine brown sugar, nuts (optional) and cinnamon; and 6 tablespoons of melted butter mix well and sprinkle evenly over batter, cover and chill overnight. In the morning, uncover and bake in a 350 degree oven for 35-40 minutes or until cake tests done with a toothpick.
