Line a 8x8 baking dish with parchment paper or foil. Set aside.
In a large saucepan, heat granulated sugar, butter, salt and heavy cream until combined. Bring to a ROLLING boil and stir continuously for 4 minutes (set your timer)!
Remove from heat. Quickly whisk in white chocolate, marshmallow and peanut butter (I usually put these ingredients in my kitchen aid and whisk them for about 1-2 minutes). Pour fudge into prepared pan and allow to set for 3 hours, until hardened.
Remove from pan, remove lining. Cut into bite sized pieces. ENJOY.
Video
Notes
For a chocolate drizzle on top, melt 1/4 cup semi-sweet chocolate morsels. Drizzle over the set fudge and enjoy.
Store fudge in airtight container at room temperature or freeze for up to three months.