In a medium bowl mix together the peanut butter, powdered sugar, vanilla extract, and salt. It will form a sort of soft dough.
Melt the chocolate in a double boiler or in the microwave in 20-second increments, being careful to not burn the chocolate.
To assemble the vegan peanut butter cups, use a chocolate mold or cupcake liners. Add just enough chocolate to the mold or cupcake liners to just cover the bottom.
Take a piece of the peanut butter dough and form a disc that is just smaller than the mold so that there is room for chocolate to go around the edges. Pop the peanut butter discs into each mold.
Now finish by pouring more chocolate overtop so that the chocolate goes around the sides of peanut butter dough and covers the top. Repeat until you run out of chocolate and peanut butter dough.
Put in the fridge to cool and set for about 30 minutes. Once the chocolate has solidified again, you can pop them out of the molds, or just trim the paper liners if you want to leave them protected. Store in an air-tight container in your cupboard.