For custard sauce, in a medium saucepan, beat eggs and granulated sugar just until combined. Stir in milk. Cook and stir over medium heat until mixture just coats a metal spoon. Remove from heat. Stir in vanilla. Cool quickly by placing pan in ice water. Pour cooled custard into a bowl. Cover surface with clear plastic wrap. Chill in the refrigerator for 1 hour.

Cut cake into 1-inch pieces; set aside. In small saucepan, heat marmalade just until melted; set aside.

Arrange half of the cake pieces on the bottom of a 2-quart glass or clear plastic serving bowl. Drizzle with half of the orange marmalade. Sprinkle with half of the chopped hazelnuts or pecans. Sprinkle with half of the liqueur or nectar. Spoon half of the custard sauce over all. Layer with remaining cake pieces, marmalade, nuts, liqueur and custard sauce. Cover; chill in the refrigerator for at least 2 hours or up to 6 hours.

Just before serving, whip cream with powdered sugar until soft peaks form (tips curl); dollop on top of dessert. Garnish with candied peel and whole nuts. Makes 6 to 8 servings.