01 - Line a 12-cup mini muffin tin with paper liners.
02 - Melt chocolate with coconut oil or butter in a heatproof bowl over gently simmering water, stirring until smooth. Alternatively, microwave in 20-second bursts, stirring between each.
03 - Spoon 1 teaspoon melted chocolate into each liner. Spread chocolate slightly up sides using back of spoon. Freeze for 10 minutes to set.
04 - Mix peanut butter, softened butter, powdered sugar, salt, and vanilla until smooth and creamy.
05 - Divide peanut butter mixture into 12 portions. Roll into balls, flatten slightly, and place one disc into each chocolate-lined cup.
06 - Cover each filling with 1 teaspoon melted chocolate, smoothing tops to seal completely.
07 - Refrigerate for 30 minutes until fully set. Remove from tin and store in airtight container for up to 1 week.