Instructions

1. Make the Crust
2. In a large bowl or food processor, mix together flour, 1/2 cup sugar, and baking powder. Cut in or pulse cold butter as for pie dough.
3. In a separate bowl, mix together 2 egg yolks and sour cream and add to the flour-butter mixture, combining or pulsing only until combined. If the dough is too dry, add an extra whole egg. If the dough is too soft to roll, refrigerate for 1 hour.
4. Lightly grease a 13x9-inch pan with butter. Roll pastry dough large enough to line the pan and come up the sides. Fit into pan, making a crimped or rolled edge. (​Note: If you have leftover dough, roll it into pencil shapes to decorate the top of the filled cheesecake.)
5. Make the Filling
6. Heat oven to 350 F. In a large bowl, cream together 5 ounces room-temperature butter with 2 cups sugar until light and fluffy. Beat in 4 large room-temperature egg yolks and vanilla until well incorporated. Thoroughly mix in the cheese.
7. In a separate bowl, beat the 4 large room-temperature egg whites to stiff peaks. Fold them into the cheese mixture. Pour filling into pastry crust-lined pan. If you have leftover dough, roll into pencil shapes and lay them diagonally across the top of the cheesecake.
8. Bake 50 to 60 minutes or until center is only slightly jiggly. Don't let the top brown. Let cool completely before serving. Refrigerate leftovers.