Prepare the Peanut Butter Filling:
In a medium bowl, combine the creamy peanut butter and softened butter. Mix until smooth and well combined.
Add the confectioners’ sugar and stir until the mixture is thick and smooth. Set aside.

Melt the Chocolate:
In a microwave-safe bowl, melt the milk chocolate chips in 20-second intervals, stirring in between until the chocolate is fully melted and smooth. Alternatively, you can melt the chocolate using a double boiler on the stove.

Assemble the Peanut Butter Cups:
Line a muffin tin with cupcake liners.
Spoon a small amount (about 1 tablespoon) of melted chocolate into the bottom of each liner. Use the back of the spoon to spread it into an even layer.
Place the muffin tin in the refrigerator for about 10 minutes, or until the chocolate has firmed up slightly.

Add the Peanut Butter Layer:
Once the chocolate layer has set, scoop about 1 tablespoon of the peanut butter mixture and form it into a small, flat disk. Place each disk of peanut butter on top of the chilled chocolate layer in each muffin liner.

Top with More Chocolate:
Spoon another tablespoon of melted chocolate over the peanut butter layer, covering it completely. Use the back of the spoon to smooth the chocolate out evenly.

Chill the Peanut Butter Cups:
Place the muffin tin in the refrigerator for about 1 hour, or until the chocolate has fully set and hardened.