Preparation Steps

• Preheat your oven to 350°F (175°C) and grease a baking dish. In a large bowl, whisk together the melted butter and sugar until combined. Then, add the eggs one at a time, mixing well after each addition. Stir in the cocoa powder, flour, baking powder, and salt until the batter is smooth.
• Pour half of the brownie batter into the prepared dish and spread it evenly. In another bowl, mix the peanut butter with a bit of the remaining brownie batter until combined. Dollop this creamy mixture over the brownie layer and swirl it gently with a knife.
• Top the swirled mixture with marshmallows, then pour the remaining brownie batter over everything, smoothing it out. Bake in the preheated oven for about 30 minutes or until a toothpick comes out with a few moist crumbs.
• Once baked, allow the brownies to cool completely before cutting them into squares. Enjoy your deliciously gooey treats with a glass of milk!