DOUGH:

4 c. flour
1 tsp. salt
1 c. (2 sticks) butter
8 oz. sour cream
2 egg yolks (reserve whites)
1 tbsp. lemon juice
Powdered sugar

Combine flour and salt in mixing bowl. Cut in the butter until grainy. In a small bowl combine the sour cream, egg yolks, and lemon juice. Blend sour cream mixture into flour mixture. Knead together to form a smooth dough. Place the dough on plastic wrap and pat it into a 6x8-inch rectangle. Wrap and chill 2 hours or overnight.

FILLING:

2 egg whites (reserved from dough)
1/2 c. sugar
1 c. walnuts, chopped fine
2 1/2 tsp. cinnamon
1/4 tsp. salt

Whip the egg whites until stiff but not dry. Gradually whip in sugar to form a meringue. Whip until the meringue holds soft peaks. Fold in remaining ingredients.

Dust a rolling pin and counter with flour. Roll dough into a thin (1/8-inch maximum) rectangle. Trim edges so the rectangle measures 24x15 inches. Cut dough into 3-inch squares and dust with powdered sugar. Place a rounded teaspoon of filling in center of each square. Dampen two opposite corners with water. Fold the two opposite corners over each other and press the center together lightly. Place on nonstick cookie sheet or bake at 350 degrees for 25-30 minutes or lightly browned.