1- First, preheat your oven to 350 degrees and grease a 9×13 inch pan to avoid any sticking. In a large bowl, mix the melted butter, brown sugar, and granulated sugar until they’re well blended that’s your base right there.

2- Next, add the eggs and vanilla extract, stirring until everything comes together smoothly. Then, beat in the peanut butter to create that creamy texture we love. In another bowl, whisk the salt and flour together before gradually adding it to the wet mix until just combined. Spread the batter into your pan and bake for 25 to 30 minutes, or until it’s golden and a toothpick comes out clean. Let the bars cool completely before moving on.

3- For the frosting, beat the softened butter with the marshmallow fluff, then slowly add the powdered sugar until it’s nice and smooth. Spread it over the cooled bars and top with chopped peanuts. This method works for vegan or gluten-free versions by swapping ingredients as needed.