Richer Than Sin White Chocolate Cheesecake

-Crust- Butter springform pan with softened butter. Combine graham wafer crumbs, melted butter, nutmeg & sugar in food processor or bowl & process until well-mixed. Press evenly over bottom & 2/3 rds up sides of pan. Set aside. -Filling- Preheat oven to 300F. Melt chocolate in double boiler. Slowly stir in cream until smooth. Remove from heat & let cool slightly. In large bowl, with electric mixer on medium speed, beat cream cheese until smooth. Add egg yolks one at a time, making sure to blend well, & stopping to scrape down the sides of the bowl after each addition. Add chocolate mixture, vanilla & salt. Beat at medium speed for two minutes. Beat egg-whites in a separate mixing bowl, with electric mixer on low speed, until foamy. Beat on high until soft, rounded peaks form. Fold egg-whites into chocolate mixture. Pour into crust. Place pan on baking sheet & bake at 300F (150C) . for 55 minutes. The cake will rise & the top will wiggle slightly when shaken. Turn off heat & let cake stand in oven for one hour (It may sink). Remove cake from oven & place on wire rack in a draft-free place & cool cake to room temperature. -Topping- Melt chocolate in double boiler. Slowly stir in cream until mixture is smooth. Stir in flavouring. Pour topping over cool cake. Cover with cello-wrap & refrigerate overnight. Three hours before serving, remove cake from refrigerator & remove side of springform. Garnish if desired.