This s'mores brownies has a rich, fudgy brownie base enveloped by a crunchy graham cracker crust, topped off with a layer of ooey-gooey melted marshmallows.
Preheat your oven to 350°F (177ºC). Line the bottom of an 8x8-inch baking dish with the graham crackers. Set aside.
Add the butter (1/2 cup), 3/4 cup of chocolate chips, and instant coffee granules (1/2 teaspoon) to a large microwave-safe bowl. Melt the ingredients for about a minute, or until completely melted. You'll need to stir the mixture vigorously to get the melted texture.
In a separate bowl, combine the sugar (1 cup) and eggs (2 eggs + 1 yolk). Use an electric hand mixer to cream the ingredients together for about 3-4 minutes, or until the mixture is light and fluffy.
Gently whisk the chocolate mixture into the egg mixture until just combined. Stir in vanilla (1 1/2 teaspoons). Gently fold the flour (1/2 cup) into the batter until no dry pockets remain, or just dissappears. Fold in the remaining chocolate chips.
Pour brownie batter over the layer of graham crackers and bake for about 28-30 minutes, or until the top of your brownies begin to look dry and a toothpick inserted in the center comes out with moist crumbs, but not batter.
Remove brownies from the oven and cool on a wire baking rack set on the counter for 45 minutes.
After the cooling period, add the marshmallows (12) on top of the brownies, then broil the brownies on high heat for 2-3 minutes, or until the marshmallows are golden brown and gooey. Slice, serve, and enjoy!