Lighten Up! Graham Cracker Cheesecake

Preheat the oven to 300 degrees F.

FOR THE CRUST:Grind the graham crackers in a food processor with the sugar to fine crumbs. (yield should be approximately 1 1/3 cups) Place in a mixing bowl. Pour the melted margarine over the crumbs, and stir to combine. Press into an 8-inch springform pan, lining the base and about 1" up the sides.

Place pan in oven to pre-bake crust for ten minutes. Remove from oven and cool while preparing filling.

FOR FILLING: Place the cream cheese, ricotta cheese and sugar in a food processor and process until smooth. (Alternatively you can use an electric mixer.) Add the egg substitute or egg whites, one at a time, mixing well after each addition. Transfer to a bowl (if using a processor) and fold in the flour, sour cream, lemon juice and lemon zest. Pour into the crust-lined pan.

Bake for 1 hour, or until the cheesecake is set in the middle. Turn off the heat and leave in the oven for an hour, with the door ajar. Remove from the oven and set aside to cool completely. Cover and refrigerate for at least 2 hours before serving.