Follow these easy steps to create your Never-Fail 4-Ingredient Peanut Butter Fudge:

1. Prepare the Baking Dish: Line an 8-inch square baking dish with parchment paper, leaving some overhang for easier removal later. Greasing the bottom lightly can also help.
2. Mix Peanut Butter and Condensed Milk: In a medium saucepan over low heat, combine the creamy peanut butter and sweetened condensed milk. Stir constantly until the mixture is smooth and well blended.
3. Add Vanilla Extract: Remove the saucepan from heat and stir in the vanilla extract, mixing thoroughly.
4. Incorporate Powdered Sugar: Gradually add the powdered sugar to the peanut butter mixture. Stir until fully incorporated and the mixture is smooth and thick.
5. Transfer to Baking Dish: Pour the fudge mixture into the prepared baking dish. Use a spatula to spread it evenly and smooth the surface.
6. Chill the Fudge: Place the baking dish in the refrigerator for at least 2 hours, or until the fudge is firm to the touch.
7. Cut into Squares: Once set, use the parchment overhang to lift the fudge out of the dish. Cut it into small squares for serving.

Now you have a delightful treat that can be enjoyed or shared!