Nanaimo Bars

Source: Canadian Living 

Yield - 1 9 inch square pan

Ingredients

 1 cup graham cracker crumbs
 1/2 cup sweetened shredded coconut
 1/3 cup finely chopped walnut
 1/4 cup cocoa powder
 1/4 cup granulated sugar
 1/3 cup butter melted
 1 egg lightly beaten

Filling:

 1/4 cup butter softened
 2 tablespoons custard powder
 1/2 teaspoon vanilla
 2 cups icing sugar
 2 tablespoons milk (approx)

Topping:

 4 oz semisweet chocolate chopped
1 tablespoon butter

Method

In bowl, stir together graham crumbs, coconut, walnuts, cocoa powder and sugar. Drizzle with butter and egg, stirring until combined.

Press into parchment paper–lined 9-inch (2.5 L) square cake pan. Bake in 350 F (180 C) oven until firm, about 10 minutes. Let cool in pan on rack.

Filling: In bowl, beat together butter, custard powder and vanilla. Beat in icing sugar alternately with milk, making 3 additions of sugar and 2 of milk and adding up to 1 tsp more milk if too thick to spread. Spread over cooled base. Refrigerate until firm, about 1 hour.

Topping: In heatproof bowl over saucepan of hot (not boiling) water, melt chocolate with butter; spread over filling. Refrigerate until chocolate is almost set, about 30 minutes.

With tip of knife, score into bars; refrigerate until chocolate is completely set, about 30 minutes. (Make-ahead: Wrap and refrigerate for up to 4 days or overwrap in foil and freeze for up to 2 weeks.) Cut into bars.