1 lb. whole milk Ricotta cheese
1 lb. sour cream
1 lb. cream cheese (2, 8 oz. pkg.)
1 1/2 c. granulated sugar
1 stick (4 oz.) salted butter, melted
3 lg. eggs
3 tbsp. flour
3 tbsp. cornstarch
1 1/2 tbsp. lemon juice
1 1/2 tbsp. vanilla extract

Have all filling ingredients at room temperature. Grease and flour the bottom and sides of a 9 x 13 inch springform pan.

In a large mixing bowl beat together Ricotta, sour cream and cream cheese until well mixed. Beat in sugar, then melted butter. Add eggs, one by one, beating well after each addition. Add flour, cornstarch, lemon juice and vanilla, beating until completely mixed.

Transfer to prepared pan and bake on middle level of a preheated 300 degree oven, for 1 hour. Turn off heat and let cake stay in oven, door closed for another hour. Remove and let cake cool in pan completely. Set on a wire rack. Cover and refrigerate for several hours. Remove sides of pan before serving.