Tall, thick and fudgy chocolate brownies with a layer of pure creamy peanut butter baked right in. These are absolutely indulgent and completely irresistible!
Preheat your oven to 350°F. Line an two (yes, 2) 8x8-inch baking pans with parchment paper leaving a 2-inch overhang along each side. You will need one to bake the brownies and one to make the peanut butter layer.
Make the peanut butter layer. Melt peanut butter in the microwave until smooth and then pour it into the lined pan. Spread it out in an even layer, then transfer to the freezer for about 30 minutes until completely firm.
Make the brownie batter. Combine chocolate and butter in a saucepan over very low heat and stir constantly until melted and smooth, or melt in the microwave at 50% power in short bursts with frequent stirring.
Combine eggs and both types of sugar in a large bowl and beat on medium-high speed using a hand mixer for 2 minutes until very pale and thick. Mix in vanilla and salt. Add the melted chocolate mixture and mix until evenly combined. Sift in the flour and fold it in so it is evenly incorporated.
Spread half of the batter evenly into the lined pan. Remove the frozen slab of peanut butter from the freezer using the parchment overhang as handles, and carefully peel off the parchment. Work quickly because the peanut butter will melt and soften fast under the warmth of your hands.
Place the slab of peanut butter over the brownie batter and gently press it down so some of the batter squeezes out the sides (to glue the rest of the batter on top). Pour the rest of the batter over the peanut butter layer and then smooth it out evenly. Bake for about 30-35 minutes until the top is puffed and shiny. Transfer to a wire rack to cool completely before slicing. Have a tall glass of milk ready!