Preheat the oven to 325 degrees F. Press the cottage cheese through a sieve and drain. In a large mixing bowl, beat the egg yolks until light an foamy, then add the sugar slowly, continuing to beat until very light and smooth. Add the cottage cheese to the egg mixture, blending well, then add the sour cream, cornstarch, lemon rind, and walnuts (if desired). Stir until all ingredients are well blended and the mixture is smooth. In another large mixing bowl, beat the egg whites until they form soft peaks, then gently fold them into the batter. Pour the mixture into the prepared crust and bake for about 1 hour. Cool to room temperature before serving.
Preheat the oven to 400 degrees F. Working on a large flat surface, such as a pastry board, place the flour and the sugar in the center of the surface and mix together. Form a small depression or well in the center of the mound. Add the beaten egg yolk and the softened butter to the well, ten blend these with the dry mixture. Mix the ingredients thoroughly using your hands -- there's no substitute for warm hands. Shape the dough into a ball and wrap in plastic wrap. Chill for at least 10 minutes. Roll out the dough to a thickness of about 1/4-inch. You should have a circle of about 11 inches in diameter. For best results, roll out your dough between 2 sheets of waxed paper, then peel away the paper and cut the crust in a 9-inch circle. Place the circle inside a 9-inch springform pan. Prick the crust
several times with a fork to keep the crust from puffing up during the baking. Place the springform pan in the oven and bake for 15 to 20 minutes, or until light brown. Allow to cool. Using the leftover dough, line the sides of the springform pan.
Press the dough against the sides of the pan, smoothing it so as to have a continuous layer of crust all the way around the sides of the pan. Make sure that the side crust meets the bottom crust all the way around. Brush the reserved egg white onto the shell, covering the bottom and sides. This will seal the dough and keep it from becoming soggy. Set aside until ready to use.
* Use from 1/4 to 1/3 cup of granulated sugar. (To Taste.)
** Separate the large egg and lightly beat the yolk.
*** Use only sweet cream, unsalted butter in this recipe. NO MARGARINE.