These s'mores brownies combine a crunchy graham cracker crust, rich fudgy brownie layer, and gooey toasted marshmallow topping for a nostalgic and indulgent dessert.
Preheat oven to 350°F (175°C) and line an 8x8-inch baking pan with parchment paper.
Mix graham cracker crumbs with 1/4 cup sugar and melted butter until combined.
Press mixture firmly into the pan and bake for 8 minutes.
Melt remaining butter with chocolate chips, stirring until smooth.
Whisk in remaining sugar, then add eggs one at a time and vanilla.
Fold in flour, cocoa powder, and salt until just combined.
Pour batter over crust and spread evenly.
Break chocolate bars into pieces and press into batter.
Bake for 15–18 minutes until edges are set but center is slightly soft.
Top with marshmallows and return to oven for 2–3 minutes until puffed.
Broil for 1–2 minutes until marshmallows are golden brown.
Cool completely before cutting and serving.
Notes
Do not overbake the brownie layer to keep it fudgy. Watch marshmallows closely when broiling to prevent burning. For clean slices, chill before cutting and use a warm knife. Store at room temperature up to 3 days.