Directions

1. Cut the margarine into the flour by stirring with a fork or a pastry blender. Mix together the 2 egg yolks and the sour cream, stir into the flour mixture. Form a ball and refrigerate overnight.
2. Preheat oven to 350 degrees F (175 degrees C). Grease clothespins lightly or cover with foil.
3. Separate the dough into 2 pieces, leave one in the refrigerator until ready to use. On a lightly floured surface, roll out the dough into a large rectangle 1/4 inch thick. Cut into strips 6x3/4 inches. Wrap loosely onto prepared clothespins. Bake for 15 minutes in the preheated oven. Remove from the clothespins while still warm. Cool before filling.
4. In a medium bowl, cream the shortening, with the margarine and sugar. Add egg whites and vanilla, beat until smooth. Add the hot milk 1 teaspoon at a time , beat until creamy. Fill the cooled cookies using a pastry bag or a plastic bag with one corner cut off.