In a medium bowl, combine graham cracker crumbs and sugar. Pour in melted butter and stir until well combined. Press the mixture onto the bottom of a 9-inch springform pan.
Bake the crust for 8-10 minutes. Remove from oven and let cool.
In a large bowl, beat cream cheese and sugar until smooth. Beat in sour cream and vanilla extract.
Stir in amaretto liqueur, if using.
Add eggs one at a time, beating well after each addition.
Pour the filling over the cooled crust.
Bake for 50-60 minutes, or until the center is almost set. Turn off the oven and let the cheesecake cool in the oven with the door ajar for 1 hour. This helps prevent cracking.
Remove from oven and let cool completely on a wire rack. Refrigerate for at least 4 hours, or preferably overnight, before serving.
Notes
Garnish with fresh berries or a dollop of whipped cream if desired.