Take two slices of bread and spread an even layer of marshmallow fluff on top.
Take another two slices of bread and spread an even layer of peanut butter on top.
Sandwich together one slice of marshmallow fluff bread and one slice of peanut butter bread, so that the marshmallow and peanut butter are touching. Repeat with the other two slices.
Now take your soft butter spread and coat the outsides of the sandwiches so that both sides are nicely coated.
In a pre-heated skillet over medium heat, lay your sandwiches down and cook until golden about 2 minutes) flip and repeat to the other side.