Bottom Layer: Melt ½ cup unsalted butter, ¼ cup white sugar, and 5 tbsp cocoa over medium heat. Add 1 beaten egg and stir to cook and thicken. Remove from heat. Stir in 1¾ cups graham wafer crumbs, ½ cup slivered almonds, and 1 cup unsweetened coconut. Press into an ungreased 9×13 pan and chill.
Middle Layer: Cream together ½ cup unsalted butter, 2 tbsp + 2 tsp cream (or milk), 2 tbsp vanilla custard powder, and 2 cups icing sugar. Beat until light. Spread over bottom layer and chill.
Top Layer: Melt 4 squares semi-sweet chocolate and 2 tbsp unsalted butter over low heat. Cool. When cool, but still liquid, pour over second layer and chill.
Keep in refrigerator.

Are graham cracker crumbs the same thing as graham wafer crumbs?
Yes. I use these.