Preheat oven to 400 degrees.
Roll the pie crust 1/4 inch thick, and cut into rectangles, about 2×3 inches each.
Place one rectangle on a lightly floured work surface, top with 1 teaspoon each of the peanut butter and preserves in the center. If you prefer, you can first mic the peanut butter and preserves, and then place 2 teaspoons of the mixture in the center of the dough.
Lightly dip your index finger into a cup of water and “brush” the border of the dough around the peanut butter mixture with the water.
Top the dough with another rectangular piece of pie dough (the water you placed on the bottom piece of dough will help the top piece adhere). Using the tines of a fork, gently press down along the edges to adhere—the tines also add a decorative effect—but make sure the peanut butter mixture stays inside the dough square.
Place the tarts on a baking sheet lined with piece of parchment paper and bake for 18 minutes or until golden. Serve when cooled.
To freeze the tarts, place them on a cookie sheet and freeze for one hour. Remove the tarts, place them in a plastic bag, label the bag, and freeze the tarts for up to 3 months. When ready to eat, follow step 6, adding an extra 2 minutes to the baking time.