Grandma's Three Layer Chocolate Squares are a family favorite treat that are served every Christmas at my house. The triple layer cookie bar consists of a chocolate graham cracker crust, a vanilla cream center and a sweet Hershey's chocolate topping. The combination is a match made in chocolate heaven.
Melt 1/2 cup butter; add one ingredient at a time, stirring after each addition: cocoa, 1/2 cup powdered sugar, egg, 2 teaspoons vanilla, graham cracker crumbs and chopped nuts. Press into the bottom of a 13x9x2 inch pan.
Melt 1/4 cup butter. In a small bowl, mix cornstarch and 2 teaspoons sugar; add to the melted butter and whisk until smooth. Add half and half or milk. Cook mixture over low heat, stirring constantly until thick and smooth; cool.
Add 1 teaspoon vanilla and 2 cups powdered sugar to cooled mixture; whisk until smooth and thick. Pour over the bottom layer and spread evenly with an offset spatula.
Melt chocolate over hot water (double boiler). Spread over the cream layer. Let cool at room temperature.
Cut into bars before the chocolate is completely set. Cut into dainty squares.