Fold chocolate crumbs and melt butter together and press into a ten inch springform pan until halfway up edges. Bake 10 minutes at 400. Reserve and hold
Mix vanilla bean with Gran Marnier and macerate for 15 minutes. Whip the cream cheese until soft. Add whole eggs and yolks and paddle until smooth with no lumps. Continuously scrape edges of work bowl. Mix sugar and cornstarch, then add to mixture. Add vanilla/Gran Marnier mixture to batter. Paddle until smooth. Pour cheesecake batter into prebaked chocolate crust. Surround springform pan with double layer of foil. Place in 4 inch deep baking pan and fill with 2 inches water. Bake for about 90 minutes at 375 until semi firm. Cool 6 hours minimum in refrigerator. Slice into desired pieces and garnish with mint, chocolate shavings, orange segments, whipped cream.