Prepare an 8"x8" square baking dish by lining it with parchment paper and set aside.
Over medium heat, combine the peanut butter, butter, vanilla, and salt in a saucepan. Cook until it's smooth, stirring frequently.
Remove from heat and with a spatula, stir in the powdered sugar.
Spread the fudge evenly in the baking sheet and top with desired toppings. Drizzle with melted chocolate.*
Refrigerate the fudge until it sets.
