In a bowl, mix the egg yolk and cream; then set aside. Add the butter or shortening and mix for about 1 minute. Then mix in the pie crust mix until evenly distributed. Add an extra tablespoon of cream if needed. Remove the dough from the bowl and form it into a ball. Place the dough on a silpat baking sheet (if you don’t have a silpat baking sheet, you can place the dough on wax paper taped onto a hard, flat surface). Then flatten the dough using your hands. With a rolling pin, roll from the center of the dough to the edge of the dough with light, even strokes, forming a large square about ¼ inch thick. Cut into even rectangles with a pizza cutter. Place the amount of jam you desire on half of the rectangles. Cover with the other half of pie crust rectangles (2 pie rectangles per pastry) and pinch edges until sealed. Gently place on a greased baking sheet and bake the pie crust for 15 minutes or until golden brown. Let pastry cool slightly, then frost and decorate as desired. Enjoy warm.