PreparationMake crust: Position rack in center of oven and preheat to 425°F. Wrap foil tightly around outside of 9-inch-diameter springform pan with 2 3/4-inch-high sides. Finely grind graham cracker cookies in processor. Add butter and process until blended. Press mixture onto bottom (not sides) of prepared pan. Set aside. For filling Blend cream cheese, 2/3 cup sugar, sour cream and cornstarch in processor. Add eggs, yolk and vanilla; process until well blended, scraping down sides of processor occasionally. Transfer 3/4 cup cream cheese mixture to small bowl; set aside. Add Frangelico, almonds and almond extract to remaining cream cheese mixture in processor. Blend well, using on/off turns. Spoon 2 1/2 cups Frangelico mixture over crust. Mix cocoa powder and 3 tablespoons sugar into reserved 3/4 cup cream cheese mixture. Spoon 2/3 cup cocoa mixture over Frangelico mixture in pan. Spoon remaining Frangelico mixture over cocoa mixture. Drop remaining cocoa mixture over by spoonfuls. Run tip of small knife through batter several times to marbleize. Bake cheesecake 10 minutes. Reduce oven temperature to 325°F and bake cake until sides are puffed and center is set, about 45 minutes. Transfer cake to rack. Using small knife, cut around sides of pan to loosen cake. Cool cake completely in pan. Cover; chill overnight. Remove pan sides from cake. Cut into wedges and serve.