Line a 24-cup mini muffin pan with paper liners (you will have a few extra on the side); set aside. *Note--if you prefer a flatter, more Reese's-like shape of cup, do not use a muffin pan. The weight of the chocolate and peanut butter mixture will spread out inside the liner making for a flatter cup. In this case, just set liners on your counter.

In a medium bowl, combine the chocolate and shortening. Melt over a saucepan of simmering water or in the microwave, stirring occasionally until completely smooth. Place about 1 1/2 teaspoons of the melted chocolate in each paper liner. Using a small, clean paint brush, brush the chocolate up the sides and the bottom of the liner to coat. (Reserve the remaining chocolate and keep warm.) Place the muffin tin in the refrigerator just until the chocolate is set, about five minutes.

Meanwhile, combine the peanut butter, sugar, butter, vanilla and salt in medium bowl using a hand held mixer until completely smooth. Using a spoon or piping bag, place the peanut butter mixture into the wells of each chocolate-coated muffin cup, about 1 1/2 teaspoons per cup. Place the muffin tin in the freezer just until the peanut butter mixture is firm, about 5-7 minutes.

Using a finger or the back of a spoon, gently press on the peanut butter mixture to smooth and flatten; allow the muffin cups to come to room temperature. Spoon the remaining melted chocolate on top of the peanut butter mixture and gently rap the muffin tin on the counter to smooth and level the chocolate. Allow the chocolate to set before serving. Enjoy!