S'mores Brownies

Preheat the oven to 350℉ (177℃). Prepare a 9x9 baking pan with nonstick cooking spray and parchment paper.
In a mixing bowl, stir together the graham cracker crumbs, granulated sugar, and melted unsalted butter. Pour the graham cracker crumbs into the prepared baking pan and spread evenly. Use a flat-bottomed measuring cup or drinking glass to firmly press the crumbs into the bottom of the pan. Set aside.

In a microwave-safe bowl, combine the unsalted butter and brown sugar. Heat in the microwave for 90 seconds until the butter is fully melted. Whisk the butter and brown sugar together until combined and smooth.
In a large mixing bowl, whip the eggs and granulated sugar with an electric hand mixer on medium-high speed for a few minutes until light and pale in color.
Slowly pour the brown sugar mixture into the egg mixture while mixing on medium speed to temper the eggs. Add in the vanilla extract and vegetable oil and mix until combined.
Add in the all-purpose flour, dark cocoa powder, salt, and baking powder and mix on low speed until combined and smooth. Fold in the milk chocolate chips.
Pour the brownie batter into the baking pan on top of the graham cracker crust and spread evenly with an offset spatula.
Bake the brownies for approximately 30 to 35 minutes until a toothpick inserted in the center comes out with wet crumbs. Remove the brownies from the oven and cool to room temperature.

Whisk together the egg whites, granulated sugar, and cream of tartar in a heat-safe bowl. (You can use the metal bowl of your stand mixer). Place the bowl over a saucepan of simmering water on the stovetop. The water should not touch the bowl. Cook the mixture, whisking constantly, for about 5 minutes until the sugar is dissolved. Test this out by rubbing a small amount of the egg white mixture between two fingers. If it is smooth and not grainy, it is ready.
Transfer the bowl or mixture to a stand mixer fitted with a whisk attachment. You can also use an electric hand mixer. Whip the egg whites on low speed for 2 minutes until frothy. Increase the speed to medium and whip until the meringue thickens. Add the vanilla extract. Continue to whip until the meringue forms soft peaks. The time this will take may vary, but typically it is about 3 to 5 minutes. The meringue will appear glossy and fold the peaks will fall over. Do not over whip the meringue as it can separate and become stiff.

Spread the marshmallow meringue on top of the cooled s'mores brownies with an offset spatula. Use a kitchen torch to carefully toast the top of the marshmallow meringue. Cut the brownies into 16 squares with a sharp knife, cleaning the knife in between slices.

Store the s'mores brownies in an airtight container at room temperature for 1 day or in the refrigerator for 2 days.

Metric conversions are calculated automatically. I cannot guarantee the accuracy of this information.