Step 1
Line one mini muffin pan with paper liners.
Step 2
In a medium bowl, using an electric mixer, beat sugar, peanut butter, butter, vanilla, and salt until well incorporated. Place peanut butter mixture between 2 pieces of parchment paper. Roll with a rolling pin to ¼-inch thickness. Using a 1-inch round cookie cutter, cut round pieces of peanut butter mixture and set aside.
Step 3
Melt chocolate chips over a double boiler. Once the chocolate is melted, pour 1/3 of the chocolate in a pastry bag. Keep melted chocolate over hot water to maintain the temperature. Add about 1 tablespoon of chocolate into the bottom of the 24 paper liners. Tap the pan to spread the chocolate in an even layer. Place in the freezer for 5 minutes until the chocolate sets. Remove pan from the freezer. Add rounds of peanut butter mix into each cup.
Step 4
Pour the remaining chocolate in a pastry bag and pipe on top of the peanut butter layer. Gently tap pan to cover all the filling. Allow the chocolate to set at room temperature for about 2 hours.