Place 3 muffin cups in the muffin pan
Melt the chocolate by microwaving in a microwave-safe bowl for 1 minute, stirring, and heating another minute. Mix in the 1 tsp of peanut butter.
In a bowl, combine the remaining peanut butter and the powdered sugar
Place about 1.5 tbsp of chocolate into each of the muffin cups, shaking tin gently side to side to get the chocolate to spread evenly along the bottom of the cups
Place about 1.25 tbsp of peanut butter into the center of each muffin cup
Place about 1.5 tbsp of chocolate into each of the muffin cups, shaking tin gently side to side to get the chocolate to spread evenly across the top of the cup, surrounding the peanut butter
Chill in fridge (or freezer) until chocolate hardens