Prep Your Pan & OvenPreheat your oven to 350°F (175°C). Line a 9×9-inch metal or glass baking pan with parchment paper, leaving a bit of overhang for easy lifting later. If you’re not using parchment, make sure to grease your pan well with nonstick spray or butter—especially in the corners. Set aside while you make your crust.

Make the Graham Cracker CrustIn a medium bowl, combine crushed graham crackers with melted unsalted butter. Stir until the crumbs are fully coated and the mixture resembles wet sand. Pour this into your prepared pan and press it down firmly using the back of a measuring cup or a clean hand—this helps form an even, tight crust that won’t fall apart later. Place the pan in the fridge while you move on to the brownie batter (this helps the crust set before baking).

Brown the ButterAdd your unsalted butter to a light-colored saucepan (this helps you see when it’s browning) and melt it over medium-low heat. Once fully melted, start swirling or stirring continuously. The butter will foam and sizzle as the water cooks off, then you’ll notice golden brown specks forming on the bottom and a toasty, nutty smell—this is what you want. This process takes about 5–10 minutes, but don’t rush it—burned butter happens fast! Once it’s a deep amber brown and smells heavenly, remove the pan from heat and let it cool for 5–10 minutes.

Make the Brownie BatterOnce your browned butter is slightly cooled (you want it warm, not hot), pour it into a large mixing bowl. Add both the light brown sugar and granulated sugar, whisking until the mixture is fully combined and glossy. Add the eggs one at a time, whisking well after each addition. This helps create that rich, fudgy texture we’re going for. Stir in the vanilla extract. Using a spatula or wooden spoon, fold in the cocoa powder and salt until fully incorporated—no dry streaks should remain. Finally, gently fold in the all-purpose flour just until combined. Try not to overmix here; we want dense, moist brownies, not cakey ones.

Bake the BrowniesRemove your crust from the fridge and pour the brownie batter directly over it. Use a spatula to gently spread the batter to the edges and smooth the top. Bake the brownies in your preheated oven for 45–55 minutes. You’ll know they’re done when a toothpick inserted into the center comes out mostly clean, with a few moist crumbs attached (you don’t want raw batter, but a little goo is good!). The top should look set and have those signature shiny cracks.

Cool CompletelyAllow the brownies to cool completely in the pan on a wire rack. This is key—if they’re still warm, the marshmallow frosting will melt and turn soupy. I usually cool them for at least an hour or two before frosting. You can even pop the whole pan in the fridge to speed it up.

Make the Marshmallow Cream FrostingSet up a double boiler: Fill a small saucepan with about an inch of water and bring it to a simmer. Place a heatproof mixing bowl (glass or metal) over the top, making sure the bottom of the bowl doesn’t touch the water. In the bowl, add your egg whites, granulated sugar, and cream of tartar. Whisk constantly for about 4 minutes, or until the sugar is fully dissolved and the mixture is warm to the touch (about 160°F if you’re using a thermometer). Once warm and smooth, transfer the mixture to a stand mixer (or use a handheld mixer) and beat on high speed for about 5 minutes until stiff, glossy peaks form. Add the vanilla extract and beat briefly to combine.

Frost & ToastOnce the brownies are fully cooled, dollop the marshmallow cream over the top and spread it into an even layer using an offset spatula or the back of a spoon. For the magic moment: use a handheld kitchen torch to toast the top until it’s golden brown and caramelized, just like a campfire marshmallow. If you don’t have a torch, you can skip the homemade cream and use regular or mini marshmallows—just pop them on top and broil for 30–60 seconds (watch closely!) until perfectly toasted. Do not broil the homemade marshmallow cream—it will melt into a puddle.

Slice & ServeOnce the frosting is set, use the parchment paper to lift the brownies out of the pan. Slice into 16 squares using a sharp knife, wiping the blade clean between cuts for the cleanest results. Serve immediately or store as directed below!