You will need a 9" springform pan or other cake pan with a removable bottom and high sides.
Preheat oven to 325°
Pulverize the graham crackers in a food processor or blender to fine crumbs.
Mix the crumbs and melted butter well, and press evenly into the bottom of the pan to form a crust. Do not go up the sides.
With an electric mixer or food processor, combine the cream cheese and sugar until very well blended, almost whipped.
Add the eggs, beating well after each addtion. Add the lemon zest, juice and vanilla.
Note: If you want to make Ridge's tradional cheesecake, omit the lemon zest and juice and add an 1 extra tablespoon vanilla.
Pour into pan and bake on middle rack of oven for 45 minutes.
Remove from oven and let cool 5 minutes.
Combine the sour cream, sugar and vanilla in a small bowl. Carefully spoon the mixture evenly over the top of the cheesecake.
Return the cake to the oven and bake another 10 minutes.
Cool completely, cover with plastic wrap and refrigerate until ready to serve.
Serves 10-12, depending on size of slice.
Recipe by Jane O'Riordan