Preheat your oven to 350°F (175°C).

Grease an 8x8-inch pan and line it with parchment paper, ensuring the edges extend beyond the sides for easy lifting.

In a bowl, mix 1 ½ cups graham cracker crumbs, 6 tablespoons melted butter, and 2 tablespoons granulated sugar until the texture is like wet sand.

Firmly pack the graham cracker mixture into the pan, pressing it down evenly to create a solid base.

Prebake for 8 minutes, then remove from the oven and let it rest while you prepare the brownie layer.

In a large bowl, whisk ½ cup melted butter and 1 cup granulated sugar until smooth.

Sift in ½ cup all-purpose flour, ¼ cup cocoa powder, ½ teaspoon salt, and ¼ teaspoon baking powder. Stir until just combined.

For extra fudgy brownies, fold in ½ cup chocolate chips.

Pour the brownie batter over the graham cracker crust, spreading it evenly.

Bake for 22–25 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.

Remove the brownies from the oven, but keep the oven on.

Sprinkle 2 cups mini marshmallows evenly over the top of the brownies.

Return the pan to the oven for 2–3 minutes, just until the marshmallows puff up and start to brown.

For a more toasted effect, use a kitchen torch to lightly toast the marshmallows until golden brown.

Let the brownies cool in the pan for at least 30 minutes to set.

Lift them out using the parchment paper overhang, then cut into squares.