Makes about 36
2/3 cup pareve margarine or butter
1/2 cup sugar
1/2 teaspoon vanilla
2 1/2-3 cups sifted unbleached all-purpose flour
1 teaspoon baking powder
Dash of salt
1. Cream the shortening with sugar. Add egg and continue creaming until smooth.
2. Add the vanilla. Stir in the sifted flour, baking powder, and salt until a ball of dough is formed (a food processor is excellent for this).
3. Chill for 2-3 hours, or overnight.
4. Preheat oven to 375 degrees.
5. Taking 1/4 of the dough, roll out on a lightly floured board to a thickness of 1/8 inch. Cut circles of dough with a drinking glass or round cookie-cutter. With your finger put water around the rim of the circle. Fill with 1 teaspoon poppy-seed or nut filling and fold into three-cornered cookies. (Press two sides together, and then fold the third side over and press the ends together.)
6. Bake on a well-greased cookie sheet 10-16 minutes, until the tops are golden.