Chocolate Hammantashen

For the filling, Put the yolk in a medium size bowl; add the other ingredients.
Mix well and wrap bowl in plastic wrap and store in the fridge until ready to use.
Be sure to let mixture come to room temperature before use.
For the dough, in a large mixing bowl, cream together the sugar and the butter.
Beat in vanilla and salt.
Add eggs one at the time. Gradually blend in flour.
Chill dough in refrigerator for 2 hours until firm enough to roll and handle.
Roll out pieces of dough to 1/4 -inch thickness.
Cut rounds with a 4-inch cookie cutter.
Place a teaspoon of filling in the center of each round.
Gather the edges of the dough around the filling and pinch at 3 points to secure seams firmly.
Bake in a preheated 375 degree oven for 15-18 minutes.
Cool on wire racks.
When the hammentashen come out from the oven, the dough will be slightly soft, but it will firm as it cools.
Good Luck!