Cream the butter or margarine and sugar together in a large mixing bowl.
Separate the eggs.
Discard the whites.
Add the yolk to the mixture and stir.
Add the flour and juices to the mixture and mix to form dough.
On a floured board, roll the dough to about 1/8inch thickness.
Use a cookie cutter to cut into 4inch circles.
Spoon a tablespoon of jam into the center of each circle and fold up 3 edges to create a triangle shape.
Leave a small opening at the center. (Other fillings, such as poppy seeds or apricot jam, can be used.)
Place the shaped dough on a cookie sheet and bake for 20 minutes in a 350degree preheated oven.
Serve for snack.