1-First Step: Preheat and Prepare the Pan Start by setting your oven to 350 F (177 C) to ensure it’s hot and ready. Line an 8 x 8 metal baking pan with parchment paper along two sides and bottom this makes removal easy later. Then, layer the 5 graham cracker sheets on the bottom, breaking them as needed to fill any gaps for a solid base.

2-Second Step: Melt the Butter and Chocolate In a microwave-safe large mixing bowl, add the ½ cup (113 g) unsalted butter and ½ cup (85 g) semi-sweet chocolate chips. Heat them in 30-second increments, stirring after each until they’re fully combined and smooth. This step takes about 1-2 minutes total and creates the rich foundation for your batter.

3-Third Step: Mix in the Sugar Stir in the 1 cup (200 g) granulated sugar just until it’s combined with the butter and chocolate mixture. Pop the bowl back in the microwave for 1 more minute, then mix everything fully. Let it sit for 5 minutes to cool to a warm temperature, which helps prevent the eggs from cooking too quickly.

4-Fourth Step: Add Eggs and Dry Ingredients Vigorously stir in the 2 large eggs for one minute until the mixture is smooth and looks ribbon-like when you lift the spoon. Next, whisk in the 1 teaspoon vanilla extract, ½ cup (40 g) unsweetened or Dutch processed cocoa powder, and ¼ teaspoon salt until it’s glossy and well-blended. Finally, whisk in the ½ cup (60 g) all-purpose flour until fully combined, making sure no lumps remain.

5-Fifth Step: Bake the Brownie Layer Spread the brownie batter evenly over the graham cracker layer in your pan, using a flexible spatula to smooth the top. Bake for about 25 minutes, then carefully take it out of the oven. At this point, the brownies should be set but still soft in the middle for that fudgy texture. For a visual check, insert a toothpick it should come out with a few moist crumbs.

6-Sixth Step: Add Toppings and Finish Baking Evenly top the brownies with 1 to 1½ cups (45 to 68 g) mini marshmallows, followed by the 1 roughly crushed graham cracker, and then the 1 (44 g) milk chocolate bar broken into pieces. Return the pan to the oven and bake for another 8 to 10 minutes, watching closely so the marshmallows turn golden without burning. This step brings out that classic smores gooeyness. Prep time is about 15 minutes, cook time is 33 minutes total, and cooling takes 1 hour, making the whole process around 1 hour and 48 minutes.

7-Final Step: Cool and Serve Let the brownies cool in the pan for 1 hour to set properly, which helps with cutting. Use the parchment paper to lift them out, then cut into squares with a sharp knife clean the knife between cuts to handle the sticky marshmallow. Serve them warm for the best flavor, perhaps with a scoop of ice cream for a twist on brownie variations, or store for later as needed.