1 lb. Ricotta cheese
16 oz. cream cheese
1/2 c. melted butter
3 tbsp. flour
5 tsp. vanilla
2 c. sour cream
1 1/2 c. sugar
3 extra large eggs
3 tbsp. cornstarch
5 tsp. lemon juice

Combine Ricotta and sour cream in a mixing bowl. Beating slowly, add cream cheese, sugar and butter. Increase speed to medium and add eggs, flour, cornstarch, vanilla and lemon juice. Beat on highest speed possible without splatting for 5 more minutes. Pour mixture into 10-inch spring-form pan and bake for 1 hour at 350°F. Turn heat off and leave in oven for 1 hour; let cool.