Quarter 1 orange, but do not peel it. Process it in a food processor until it is chopped fine, about 25 seconds. Add 2 eggs, half the sugar and half the oil. Process for 10 seconds. Add 2 teaspoons baking powder and half the flour. Process with several on/off turns just until the flour is blended into dough. Do not over process. Dough will be fairly sticky. Remove from the bowl onto a lightly floured board. Repeat the procedure with the remaining ingredients.

For the filling:
Cut the third orange into quarters, but do not peel. Process half the orange in a food processor for 20 seconds. Add half the remaining ingredients. Process until fine, about 15 seconds. Empty the processor bowl. Repeat with the remaining ingredients.

Makes 2 cups of filling.

To make the cookies, divide the dough into 4 parts. Flour each piece lightly and roll on a floured board to 1/4 inch thickness. Cut the dough into 3 inch circles. Place a spoonful of filling on each circle. Bring the sides towards the center and pinch to form a triangle (see the images below for how to shape the hamentashen cookies).

Place the shaped and filled cookies on a greased cookie sheet. Brush them with an egg yolk which has been blended with 1 teaspoon water.

Bake at 350°F for 25-30 minutes.