Combine egg yolks and sugar in a double boiler over boiling water. Mix with wire whip for about three minutes. Combine Mascarpone, pumpkin puree, spices and maple syrup in a food processor and puree until smooth. Remove mixture from food processor and fold together with egg mixture. Place in refrigerator to chill while making whipped topping.
For topping, combine all ingredients in a mixer and whip until smooth and light, about 4 minutes on medium-high speed. Remove and place into pastry bag. Layer pumpkin mixture and whipped topping in glass and top with the shaved chocolate and chocolate wafer and serve.