Nanaimo Bars

(16 tablespoons)(1/2 pound) unsalted butter, softened (and divided)

granulated sugar, divided

unsweetened cocoa powder

extra-large egg, at room temperature, lightly beaten

graham cracker or ‘nilla wafer crumbs, finely ground

shredded coconut (sweetened or unsweetened – I used unsweetened)

coarsely chopped walnuts or pecans (optional – I opted out & didn’t use nuts)

cream, divided

Bird’s custard powder (or instant vanilla pudding)

confectioner’s sugar

unsweetened chocolate