Prepare your paper liners by putting them into a muffin tin, which will help keep them still as you work. You will need about 12 for regular-sized paper liners. You can skip this step if you are using chocolate molds or opting for chocolate covered peanut butter balls!
Stir together the peanut butter, vanilla extract, salt, and powdered sugar. You may need to add more powdered sugar to get the desired consistency. You should be able to roll the peanut butter filling into a ball that holds its shape.
Prepare peanut butter filling by taking out approximately two teaspoons at a time and forming them into small disks. These disks should be smaller than the width of your cupcake liners, so that the peanut butter filling will be nice and hidden inside the chocolate shell. Put these disks on a plate or cookie sheet in the fridge during the next step.
Melt chocolate and coconut oil, stirring to combine. You can melt using a double boiler, the microwave, or by placing chocolate and coconut oil in a heat safe bowl within a large pot filled with a couple inches of water (I used this method). Bring the water to a simmer, stirring chocolate until its melts. Once melted, remove pot from heat but leave the bowl of chocolate inside so it stays melted while you work.
Spoon just enough chocolate into the liners to cover the bottom, about 1-2 teaspoons.
Place peanut butter disks on top of first layer of chocolate, in the center of each liner.
Cover each disk with more melted chocolate, about 2 teaspoons. You can slightly tilt the muffin tray to move the chocolate around, or use your spoon to gently push the chocolate around. This can also give you a nice swirl on top of your chocolate!
Put the muffin tray in the refrigerator for 30 minutes to let the chocolate set.
Remove from fridge and enjoy! Store in an airtight container in cool, dry place.