Remove peanut butter cup wrappers and cut candies into fours.
Line 9x9-inch pan with parchment.
Place white chocolate chips and marshmallow fluff in a big bowl. Set aside.
In a pan, melt sugar, heavy cream, salt, and butter on medium heat until it starts to boil. Cook for 5 minutes.
Pour hot mixture into bowl of chocolate chips and mix with blender until smooth and soft.
Fold in half of the peanut butter cups. Pour into pan.
Sprinkle remaining peanut butter cups on the top. Put in the fridge for 3 to 5 hours to set.
