Process almonds in a food processor until ground; add 1/4 cup sugar and butter, and process until blended. Press into bottom and 1 1/2 inches up sides of an aluminum foil-lined 9-inch springform pan.
Bake at 400° for 10 minutes. Cool on a wire rack.
Beat cream cheese, remaining 3/4 cup sugar, and vanilla at medium speed with an electric mixer until smooth. Add eggs and yolks, 1 at a time, beating well after each addition. Add flour; beat until smooth. Add whipping cream and amaretto; beat until blended. Spoon into crust.
Bake at 400° for 10 minutes. Reduce temperature to 350°, and bake 30 minutes or until center is firm. Turn off oven. Let cheesecake stand in oven, with oven door closed, 30 minutes. Remove from oven; cool in pan on a wire rack 30 minutes. Cover and chill 8 hours.
Invert cheesecake onto serving dish. Garnish, if desired.