1 lb. Ricotta cheese, room temperature
2 (8 oz.) pkgs. cream cheese, room temperature
1 1/2 c. sugar
4 eggs
1/2 tsp. lemon juice
1/2 tsp. vanilla
3 tbsp. cornstarch
3 tbsp. flour
1/4 c. melted butter
1 pt. sour cream

Blend Ricotta and cream cheese well. Blend in sugar. Beat in eggs, one at a time. Add vanilla, lemon juice, cornstarch, flour, and butter. Fold in sour cream and blend well. Pour into 10 inch buttered spring-form pan. Place in cold oven and bake at 350 degrees for 1 hour. DO NOT OPEN OVEN DOOR. Turn off oven and leave in there for at least 3 hours. Cover with pie filling.