• The first step is to place one of the oven racks in in the center of the oven and preheat the oven to 325˚ degrees Fahrenheit.
• Use nonstick cooking spray to evenly coat an 8x8 baking pan, and then line the pan with parchment paper. This step helps you to easily remove the bars from the pan after baking.

Prepare the brownie layer:

• Use a microwave safe bowl or dish and melt 6 tablespoons of unsalted butter for the brownie mix. Once the butter is melted, pour it into a large mixing bowl and allow it to cool for a few minutes.
• Once the butter has cooled slightly, add in the brownie mix, and stir until combined. Next you will stir in 2 tablespoons of heavy whipping cream and ⅛ teaspoon of salt. Once everything is mixed in, add the egg and egg yolk, and stir until everything is fully mixed.
• Pour the brownie mixture into the prepared 8x8 pan and spread it out evenly using a spatula.

Add marshmallow creme and chocolate chip layers:

• Next you will spread the 1 cup of marshmallow creme evenly on top of the brownie layer. I like to keep the creme just slightly away from the edges of the edges of the pan. Start by putting the marshmallow creme in the center of the pan and spread it out to the sides. The marshmallow creme is sticky to work with, so take your time spreading it into an even layer.
• Sprinkle ½ cup of semi-sweet chocolate chips on top of the marshmallow creme layer, followed by 1 cup of the rough chopped graham cracker pieces.

Prepare the cookie layer:

• In a clean mixing bowl add the cookie mix, 4 tablespoons of all-purpose flour, 2 tablespoons of heavy whipping cream, ¼ cup of softened room temperature butter, ¼ cup light brown sugar, 1 tablespoon of vanilla bean paste, and ⅛ teaspoon of salt, and stir until everything is combined. The cookie dough will be thick and firm.
• Divide the cookie dough into 4-5 balls and press them in your hand to flatten them out and place them on top of the marshmallow creme layer. Make sure you can still see some of the marshmallow creme below.

Bake:

• Bake the s’mores bars at 325˚ Fahrenheit for approximately 40-50 minutes. Oven times do vary, so be sure to insert a toothpick or knife in the center of the pan to check the bars and ensure they are done. You want to make sure not to overbake the bars, they should still be soft. The bars will continue to set up as they cool, and they taste best when they are soft and gooey!
• Once you determine the s’mores bars are done baking, remove the pan from the oven and transfer it to a wire rack to cool to room temperature. While the bars are still warm, press into the top ½ cup of chocolate chips, the ½ cup of rough chopped graham crackers and ½ cup mini marshmallows. Next, as an optional garnish, sprinkle the bars lightly with flakey sea salt on top.
• Once the bars have cooled to room temperature, use the parchment paper to lift them from the pan and cut the bars evenly into 16 pieces.