Nanaimo Bars - In time for Christmas!

I love these bar cookies. My friend Kimberley gave me the recipe. She only makes them around Christmas. I'm inclined to make them anytime, certainly anytime in the winter. When my aunt, a caterer, made them for a party, they disappeared before anything else.

INGREDIENTS
1/2 cup butter, softened
1/4 cup white sugar
5 tablespoons unsweetened cocoa powder
1 egg, beaten
1 3/4 cups graham cracker crumbs
1 cup flaked coconut
1/2 cup finely chopped almonds (optional)
1/2 cup butter, softened
3 tablespoons heavy cream
2 tablespoons custard powder
2 cups confectioners' sugar
4 (1 ounce) squares semisweet baking chocolate
2 teaspoons butter

DIRECTIONS
In the top of a double boiler, combine 1/2 cup butter, white sugar and cocoa powder. Stir occasionally until melted and smooth. Beat in the egg, stirring until thick, 2 to 3 minutes. Remove from heat and mix in the graham cracker crumbs, coconut and almonds (if you like). Press into the bottom of an ungreased 8x8 inch pan.
For the middle layer, cream together 1/2 cup butter, heavy cream and custard powder until light and fluffy. Mix in the confectioners' sugar until smooth. Spread over the bottom layer in the pan. Chill to set.
While the second layer is chilling, melt the semisweet chocolate and 2 teaspoons butter together in the microwave or over low heat. Spread over the chilled bars. Let the chocolate set before cutting into squares.