Prepare the Muffin Tin: Line a muffin tin with paper liners.

Make the Peanut Butter Filling: In a mixing bowl, combine the creamy peanut butter and powdered sugar. Mix until smooth and well combined. Set aside.

Melt the Chocolate: In a microwave-safe bowl, combine the milk chocolate chips and vegetable oil. Microwave in 30-second intervals, stirring in between, until melted and smooth.

Layer the Chocolate: Spoon a small amount of melted chocolate into the bottom of each muffin liner. Spread it slightly up the sides. Refrigerate for 10-15 minutes to set.

Add the Peanut Butter Filling: Take a small portion of the peanut butter mixture and roll into balls that fit inside the chocolate cups. Flatten slightly if needed, and place one in each cup.

Top with More Chocolate: Spoon the remaining melted chocolate over the peanut butter filling until fully covered. Smooth the tops with a spatula.

Chill: Return to the refrigerator and let the cups chill for at least 30 minutes or until completely set.

Serve: Once set, remove the peanut butter cups from the muffin tin and peel off the liners. Sprinkle a pinch of sea salt on top if desired.

Enjoy: Indulge in your homemade Reese’s Peanut Butter Cups!