Drizzled Chocolate Mint Bars

[Cookie]

1 cup chocolate mint chips
1/4 cup butter or margarine
1/4 cup icing sugar
1 egg
1 1/2 cups graham crumbs
1/2 cup walnuts
1/4 cup butter or margarine
2 cups icing sugar
2 tbsp. milk
Green food coloring (optional)
3 dozen
Melt chocolate and first amount of butter over hot water.
Reserve 1/4 cup for top drizzle.
Add first amount of icing sugar and egg to remaining melted chocolate.
Beat well.
Stir in graham crumbs and walnuts.
Press into bottom of 8" pan.
Chill.
Cream second amount of butter, second amount of icing sugar and milk until fluffy.
Add green food coloring if desired.
Spread over base in pan.
Drizzle reserved melted chocolate over top.
Chill until firm.
Cut into bars.