Line a mini muffin tin with 24 paper liners.
Melt 1 cup of chocolate chips in the microwave in 30-second intervals, stirring until smooth.
Spoon about 1 teaspoon of melted chocolate into each liner, just enough to cover the bottom. Refrigerate for 10 minutes.
Meanwhile, mix together peanut butter, powdered sugar, butter, vanilla, and salt until smooth and well combined.
Roll peanut butter mixture into 24 small balls and flatten slightly. Place one on top of each chocolate base.
Melt remaining chocolate chips and spoon over peanut butter layer, covering completely.
Refrigerate for at least 30 minutes until set. Store in refrigerator for up to 2 weeks or freeze for up to 3 months.