Creme de Menthe Squares

1 1/4 cups butter or margarine
1/2 cup unsweetened cocoa powder
3 1/2 cups powdered sugar -- sifted
1 egg -- beaten
1 teaspoon vanilla
2 cups graham cracker crumbs
1/3 cup creme de menthe
1 1/2 cups semi-sweet chocolate chips

For bottom layer: In sauce pan combine 1/2 cup of the butter and the cocoa powder. Heat and stir until well blended. Remove from heat; add 1/2 cup of the powdered sugar, the egg and vanilla. Stir in graham cracker crumbs. Mix well. Press into bottom of an ungreased 13x9x2" baking pan.

For middle layer: Melt another 1/2 cup of the butter. In small bowl combine the melted butter and creme de menthe. At low speed of electric mixer beat in the remaining 3 cups powdered sugar until smooth. Spread over the chocolate layer. Chill 1 hour.

For top layer: In small sauce pan combine the remaining 1/4 cup butter and chocolate pieces. Cook and stir over low heat until melted. Spread over middle layer. Chill 1 to 2 hours. Cut into small squares. Store in refrigerator.