Step 1

Butter an 8x8 baking dish or cover with parchment paper, making sure to leave plenty of parchment hanging over the sides.

Step 2

In a large pot over medium heat, melt the butter and peanut butter, stirring occasionally. Bring to a boil and remove from heat.

Step 3

Stir in the salt and vanilla extract until smooth. Add the powdered sugar and mix until well combined and smooth with no lumps remaining.

Step 4

Pour the fudge mixture into the prepared baking dish and use the back of a spoon to smooth into an even layer. Place plastic wrap over the dish and gently press down on the top of the fudge to cover. Refrigerate for 1 hour before slicing.