1. Preheat oven to 350 degrees Fahrenheit (180 degrees Celsius). Combine all crust ingredients and press into nine-inch round pan or oven-to-tableware. Bake for 15 minutes.
2. In a double boiler, melt margarine and chocolate. Stir beaten eggs into the melted margarine and chocolate. Slowly stir in the confectioners’ sugar until smooth. Remove from flame, then add the vanilla. Stir until smooth. Pour toffee mixture over crust. Freeze until firm.
3. Meanwhile, beat the whipping cream until stiff peaks form. Add in coffee, vanilla extract, and vanilla sugar. Smooth topping over the frozen toffee layer and return pie to freezer.
4. Once fully frozen, you can decorate with crushed Viennese crunch, shredded chocolate, or chocolate curls.