Line an 8x8 inch pan with parchment paper and set aside.
In a large bowl, combine the peanut butter and the softened butter together with an electric hand mixer until a smooth mixture forms. Slowly add the powdered sugar and mix. Add in the vanilla extract and the salt and mix again until combined.
2 cup creamy peanut butter, ½ cup butter, ½ teaspoon salt, 1 teaspoon vanilla extract, 3 & ½ cup powdered sugar
Press the mixture into the prepared pan and gently spread it into an even layer.
Add the chopped-up chocolate and butter to a microwave-safe bowl and melt in the microwave in 30-second increments. Stirring in between each time.
12 oz chocolate, 3 tablespoons butter
Pour the melted chocolate on top of the peanut butter layer and gently spread it to cover the whole top of the peanut butter bar.
Allow the bars to set in the fridge for 10-20 minutes or until the chocolate is no longer melted.
Using a sharp warmed up knife, slice your bars and enjoy! (Read the notes for tips)