Prepare the Fudge Base

1. Line the Pan: Line an 8×8-inch baking dish with parchment paper, allowing some overhang for easy removal. Lightly grease the parchment with butter or cooking spray.
2. Melt Peanut Butter and Butter: In a medium saucepan, combine the peanut butter and butter. Heat over medium-low, stirring frequently, until fully melted and smooth.
3. Add Vanilla: Remove from heat and stir in the vanilla extract.

Combine with Powdered Sugar

4. Sift the Powdered Sugar: To avoid lumps, sift the powdered sugar into a large mixing bowl.
5. Mix Together: Pour the melted peanut butter mixture over the powdered sugar. Stir vigorously with a wooden spoon or silicone spatula until the mixture is smooth and no dry spots remain.

Shape and Chill

6. Transfer to the Pan: Spread the mixture evenly into the prepared baking dish, pressing it down with a spatula or your hands for a smooth surface.
7. Add Toppings (Optional): Sprinkle chopped nuts, chocolate chips, or sea salt flakes on top if desired.
8. Chill: Refrigerate for at least 2 hours or until the fudge is firm and set.