01 -  Line each well of a 12-cup mini muffin pan with paper liners. 
 02 -  Combine semi-sweet chocolate and coconut oil in a heatproof bowl and melt over simmering water or microwave in 20-second intervals, stirring until completely smooth. 
 03 -  Spoon approximately 1 teaspoon of melted chocolate into the bottom of each liner, tilting the pan or using a spoon to coat the base evenly. Transfer to the freezer to chill for 10 minutes. 
 04 -  In a separate bowl, blend creamy peanut butter, powdered sugar, softened unsalted butter, and a pinch of salt until the mixture is well combined and thick. 
 05 -  Divide the peanut butter mixture into 12 portions (about 1 teaspoon each), roll into balls, and flatten slightly to form discs. 
 06 -  Place a peanut butter disc onto each chilled chocolate base. 
 07 -  Top each filling with another teaspoon of melted chocolate, ensuring the centers are fully covered. 
 08 -  Gently tap the pan to level the tops, then refrigerate for 30 minutes or until completely set. 
 09 -  Store finished cups in an airtight container in the refrigerator for up to one week.