6 to 8 graham crackers made into crumbs
1 lb. Ricotta cheese
2 (8 oz.) cream cheese, softened
1 1/4 c. sugar
4 eggs, slightly beaten
1/3 c. cornstarch
2 tbsp. lemon juice
1 tsp. vanilla
1/2 c. butter, melted (no substitute)
1 (16 oz.) sour cream

Grease 9 x 3 1/4 inch springform pan, dust with graham cracker crumbs. In large bowl, mix ricotta cheese with cream cheese. Beat at high speed, blend in sugar, then eggs. Reduce speed to low; add cornstarch, lemon juice, and vanilla. Beat until blended. Add butter and sour cream. Blend on low speed. Pour into prepared pan. Bake in 325 degree oven 1 hour 10 minutes; or until firm around edges. Turn off oven. Let cake stand in oven 2 hours. Remove and cool completely on wire rack. Chill. Remove sides of pan.