I had to chuckle when I heard that this was the most popular dessert at the Vancouver Olympics. My recipe is so old the paper has yellowed! We've been eating Nanaimo Bars for a long time, and yes, they really did originate in Nanaimo, BC.
When I make them, it's pretty much an all-in-one-go type of process. Each layer chills while the next is made, although adding the chocolate on top can make the middle messy if it hasn't chilled enough.
Here you go, the original recipe.
Bottom:
1/2 cup melted butter
1/4 cup sugar
5 tbsp cocoa powder
1 tsp vanilla
1 egg
2 cups graham wafer crumbs
1 cup coconut
1/2 cup chopped walnuts
Mix the first five ingredients together (butter, sugar, cocoa, vanilla, egg) so that it resembles custard. Add remaining ingredients and mix well. Press into an 8"x8" pan. Chill.
Filling:
1/4 cup butter
3 tbsp milk
2 tbsp vanilla custard powder (Bird's Eye)
2 cups icing sugar
Make an icing by creaming together filling ingredients. Spread onto chilled bottom layer. Chill.
Icing:
4 oz semi-sweet chocolate
1 tbsp butter
Melt together over hot water. Pour and spread evenly over chilled filling. Chill well.
Cut into squares and serve.