Line an 8x4 inch loaf pan or an 8x8 inch square pan with parchment paper, leaving an overhang for easy removal.

In a medium saucepan over low heat, combine the creamy peanut butter and unsalted butter.

Stir the mixture continuously with a whisk until the ingredients are fully melted and the texture is smooth.

Remove the saucepan from the heat immediately to avoid scorching the oils.

Add the powdered erythritol, vanilla extract, and sea salt to the mixture.

Whisk vigorously until the sweetener is completely incorporated and the mixture is glossy and lump-free.

Pour the fudge mixture into the prepared pan and spread evenly using a silicone spatula.

Refrigerate for at least 60 minutes or until the fudge is firm and completely set.

Lift the set fudge out of the pan using the parchment paper edges and slice into 16 equal squares.