Molten chocolate mugs

1 1/4 c semi-sweet chocolate chips
6 TBS butter (not margarine)
4 eggs
1/4 c sugar
combine chocolate and butter in a mixing bowl and melt in a double boiler(I use a glass mixing bowl over a pot of boiling water); combine eggs and sugar in a mixing bowl until fluffy, remove chocolate mixture from heat. Fold the egg mixture into the chocolate mixture until smooth, spoon even amount into 4 hot chocolate mugs till about 3/4 full bake at 350 for 17-20 minutes