I don't know if this is what you are looking for, but I found this recipe online:
MOM'S PEANUT BUTTER MARSHMALLOW FUDGE
1 c. white sugar
1 c. brown sugar
2 tbsp. butter
1 tsp. vanilla
1/2 c. peanut butter
1/2 jar marshmallow fluff
1/2 c. evaporated milk
Pinch of salt
Cook sugar, butter, milk, and salt until soft ball. Add marshmallow fluff, peanut butter and vanilla. Beat until creamy and thick. Pour into buttered dish. Found it here:
http://www.cooks.com/rec/doc/0,167,146169-227200,00.html
Here's another one:
Peanut Butter Fudge with the Marshmallow Fluff
2 cups sugar
1 cup milk
1 jar peanut butter (12oz.) smooth or crunchy
1 jar marshmallow Fluff (also called creme)
1 tsp. Vanilla extract
Boil 2 cups sugar and 1 cup milk to soft ball stage. Remove from heat and
add 1 jar peanut butter, and 1 jar marshmallow fluff, add vanilla. Pour
into a buttered pan 8x8x8-inch. Let cool and cut into squares.
Have sprinkled red and green sugar on for the holidays too.
Got that one here:
http://www.cdkitchen.com/recipes/recs/35/Peanut_Butter_Fudge_with_the_Marshmallow_Fluff42723.shtml