Preheat oven to 350°F and line an 8×8 pan with greased parchment paper, leaving extra hanging over the side to act as handles later.
To make the cookies, melt butter and add the brown erythritol, baking soda, cinnamon, and Keto Chow. Stir well.
Smooth the mixture into the prepared pan and bake for 10-15 minutes, or until golden brown.
To make the ganache, heat the heavy cream for one minute in the microwave. Add the chocolate chips and let sit for one minute and then stir until thick, smooth, and creamy.
Once the cookies have cooled for five minutes, spread the ganache evenly on top and let set in the refrigerator for 30 minutes.
While the ganache is setting, make the marshmallow fluff. Whip the egg whites, cream of tartar, and vanilla on high speed with a mixer until stiff peaks form. Continue to whip the mixture, adding in 1/3 of the allulose at a time, waiting 30 seconds between each addition. After all allulose has been added, whip for another couple of minutes.
Top the s’mores with the marshmallow fluff once the ganache has cooled. Broil for one minute in the oven. It browns fast so watch it closely!
Refrigerate for at least another 30 minutes before serving.