Gleaned from two different Canadian Living recipes and personal experience.
To make the crust, mix a cup of melted butter, a half cup of sugar, 2/3 of a cup of cocoa, two eggs, 2 cups of graham cracker crumbs, one cup of unsweetened coconut, and 2/3 of a cup of chopped walnuts. Press into 2 greased and lined 9 x 9 pans. Bake at 350 for 10 minutes or just chill.
To make the filling, cream together 3/4 of a cup of butter, 6 tablespoons of custard powder, 3 teaspoons of vanilla, and then alternate adding 9 tablespoons of milk with 6 cups of icing sugar. Colour with yellow food colouring, if desired, and smooth over cold base. Chill for an hour.
To make the chocolate, melt 8 ounces of semi sweet chocolate with 3-4 tablespoons of butter, and spread over the cold icing layer. Chill; slice.