In a microwave-safe bowl, melt the chocolate chips with 1 tablespoon of peanut butter. Stir until smooth. Spoon about 1 teaspoon of the chocolate mixture into the bottom of each liner.
In a separate bowl, mix the remaining peanut butter, powdered sugar, softened butter, and vanilla extract until well combined.
Spoon about 1 teaspoon of the peanut butter mixture on top of the chocolate in each liner.
Top with the remaining chocolate mixture, spreading it to cover the peanut butter layer.
Refrigerate for at least 15 minutes, or until firm.