01 -
Line an 8-inch square pan with parchment paper, leaving extra parchment over two sides for lifting the fudge out later.
02 -
Add the peanut butter and butter to a medium saucepan. Warm over low heat, stirring often, until smooth, glossy, and fully combined, about 3-4 minutes.
03 -
Remove the pan from the heat. Stir in the vanilla extract until evenly mixed.
04 -
Add the powdered sugar in two additions, stirring well after each one. The mixture should become thick, matte, and dough-like with no dry pockets.
05 -
Scrape the fudge into the prepared pan. Press it firmly into an even layer and smooth the top with parchment or a spatula.
06 -
Refrigerate for at least 2 hours, or until firm. Lift out the slab and cut into 36 small squares with a warm, dry knife.