A Nanaimo Bar is a triple layered dessert bar. It is quite sweet, and very very rich. Eat too many of these and you will be feeling sick. You will, however, have enjoyed the eating process. Damn, these are tasty.
Bottom Layer
Melt butter with sugar and cocoa in top of a double boiler. Add the egg and stir until thick. Remove from heat. Stir in crumbs, coconut and nuts. Press firmly into an ungreased 8-inch by 8-inch pan. Chill at least 20 minutes.
Middle Layer
Mix the butter, cream, custard powder, and icing sugar together. Beat until light. Spread over bottom layer. Chill another 15 minutes.
Top Layer
Melt chocolate and butter over low heat. Cool a bit, but while it's still liquid, pour over the middle layer and chill at least an hour. Serve chilled.
The origins of the Nanaimo Bar probably lie in dessert bars that were often sent by the families of coal miners, back when Nanaimo was mostly a coal mining town.
The first recipe called a Nanaimo Bar was published in 1957 in the "Favourite Recipes, Compiled by the Women's Association of the Brechin United Church" of Nanaimo, British Columbia. It was submitted by Joy Willgress.
In 1986, one of the newspapers in Nanaimo held a contest to determine "the best Nanaimo Bar maker in Nanaimo." The winning recipe, by Joyce Hardcastle, is the one that you're most likely to stumble across, and is the one that I have up top.
Sources:
http://www.tourism.nanaimo.bc.ca/visitorinfo_nanaimobar.asp
http://www.expage.com/page/nanaimobar