Peanut Butter Fudge

Cut a 22-inch-long piece of parchment paper and fold over the edges so it measures 8 inches wide; set it aside. Coat an 8-by-8-inch baking dish with butter and line it seam-side down with the parchment (the 2 long ends will hang over the edges). Be sure to fit the parchment as smoothly as possible into the dish, snugly creasing it into the corners; set the dish aside.

Heat the measured butter and vanilla in a medium saucepan over medium heat until the butter has melted. Stir in the brown sugar and cream and bring to a full boil. Continue boiling, stirring constantly, for 2 minutes more. Stir in the peanut butter until smooth.

Remove from the heat and set aside to cool for exactly 5 minutes (it will form a skin).Immediately transfer the mixture to the bowl of a stand mixer fitted with a paddle attachment. Turn the mixer to medium-low speed and gradually add the powdered sugar until all of it is incorporated (the mixture will look slightly curdled and sandy).Quickly scrape the mixture into the prepared baking dish and pat into an even layer. Use a paper towel to blot the excess oil off the surface.

Sprinkle the peanuts evenly over the top.Fold the excess parchment paper over the fudge. Using a measuring cup, press down on the parchment to press the peanuts into the fudge and evenly flatten the surface. Uncover the fudge and let it sit at room temperature until completely cooled, about 2 hours.To remove the fudge from the pan, grip the parchment hanging over the edges and pull it out of the dish (if the fudge cracks, just press it back together).

Transfer it to a cutting board and, using a long knife, cut it into 64 (1-inch) pieces, wiping the knife clean between slices. Though best eaten right away, the fudge can be stored at room temperature in an airtight container for up to 3 days.