Nanaimo Bar Brownies

Preheat oven to 325°f.

Place a rack in the middle position of the oven.

Melt chocolate and butter in a heavy saucepan over low heat.

Remove from heat and stir in sugar.

Add eggs and vanilla and beat well. Stir in flour, salt and walnuts.

Mix well.

Pour into a well-greased baking pan.

Bake for 40 minutes.

Remove from the oven and let cool completely.

While the brownies cool, prepare the middle layer. In a stand mixer fitted with the paddle attachment, cream the butter, cream, custard powder, and confectioners' sugar together until very light and fluffy.

Spread over the bottom layer, taking care to spread it as flat and evenly as possible. Return the pan to the refrigerator while you prepare the topping.

Prepare the top layer: in a medium saucepan or double boiler, melt the chocolate and butter over medium heat, stirring often to ensure that the mixture doesn't scorch.

Remove from heat.

Let sit until the mixture is still liquid but very thick, then pour it over the second (middle) layer and gently spread it with a spatula to ensure even coverage (but work carefully, because the still-warm chocolate will get messy if you press too hard while spreading it and tear up the buttery layer below).

Let the bars cool for at least one hour in the refrigerator before serving.