01 - Line a 12-cup mini muffin tin with paper liners
02 - Melt chocolate in a heatproof bowl set over a pan of simmering water (double boiler method), or microwave in 30-second bursts, stirring until smooth
03 - Spoon about 1 teaspoon of melted chocolate into the bottom of each liner. Tilt or tap the tin to evenly coat the base
04 - Place the tin in the freezer for 10 minutes to set the chocolate base
05 - In a bowl, mix together peanut butter, melted butter, powdered sugar, vanilla, and salt until smooth and creamy
06 - Remove the tin from the freezer. Drop a rounded teaspoon of the peanut butter mixture onto the center of each chocolate base, flattening gently without touching the sides
07 - Spoon the remaining melted chocolate over the peanut butter filling, ensuring it's fully covered. Tap the tin gently to smooth the surface
08 - Chill in the refrigerator for at least 30 minutes, or until completely set
09 - Remove from liners and serve chilled or at room temperature