Start by greasing an 8x8-inch square baking dish or lining it with parchment paper. A little oil or cooking spray can prevent sticking, allowing you to lift the fudge out easily later. Set this aside.

In a medium saucepan, combine the unsalted butter, brown sugar, and whole milk. Over medium heat, stir everything together until the mixture starts to boil. Keep stirring carefully! You don’t want to scorch it on the bottom. Once you see bubbles forming, allow it to boil for about 2 minutes while stirring continuously.

After boiling, remove the saucepan from heat. Add the creamy peanut butter and vanilla extract. Stir until it’s well combined and smooth. Be prepared for that beautiful, nutty aroma to fill your kitchen.

Next, sift the powdered sugar into the mixture. This step is crucial for getting that silky texture. Stir with a wooden spoon or rubber spatula until everything is thoroughly combined and there are no lumps left.

Now, pour the luscious peanut butter fudge mixture into the prepared baking dish. Use a spatula to smooth it out evenly. Don't worry about being perfect; a little rustic charm makes it even more delightful!

Place the fudge in the refrigerator to set. It will need about 2 to 3 hours to firm up. Patience isn’t always my strong suit, but trust me, it’s worth the wait!