Preparation / Directions:
Beat ricotta until smooth, gradually add 1 1/2 cups sugar and egg yolks, beating after each addition. Beat in flour, lemon rind and vanilla. Beat egg whites with 1/2 cup sugar. Fold whipped cream and egg whites into ricotta mixture and turn into a 12" spring form pan which has been well-buttered and sprinkled with graham cracker crumbs. Bake in a preheated 425 degree oven for the first 10 minutes; lower temperature to 350 degrees and bake for 1 hour. Turn off heat and allow to cool in oven with door closed. Freezes well. Dust with powdered sugar when served.