Preheat oven to 350F. Line baking sheets with parchment or Silpats (see note). Set aside.
In a medium bowl, combine dry ingredients (flour, graham flour [see note], baking soda, salt, and cinnamon). Set aside.
In the bowl of a stand mixer, combine butter, brown sugar, and granulated sugar. Beat until light and fluffy. Scrape down the sides of the bowl.
Add honey, egg, and egg yolk. Mix to combine. Scrape down the sides of the bowl.
With the mixer running on low speed, gradually add the dry ingredients. Mix until just incorporated.
Using a large cookie scoop (about 2 tablespoon in size...see note), scoop the dough onto the prepared baking sheets, placing dough balls about 2 inches apart.
Bake 8-10 minutes. Allow to cool on baking sheet five minutes, then remove to wire racks to cool completely.
For Ganache:
Combine chopped chocolate and heavy cream in a small heatproof bowl. Microwave 30 seconds. Allow mixture to sit for about one minute, then mix until smooth. If mixture is not smooth, return to microwave on 15-second bursts until completely melted and smooth.
Spoon ganache onto the bottoms of half of the graham cookies.
For Marshmallow Cream:
In the bowl of a stand mixer, combine egg whites and cream of tartar. Fit the mixer with the whisk attachment. Move on to the next step.
In a small saucepan, combine sugar, agave, water, and salt. Over medium-high heat, whisking occasionally.
When the sugar mixture reaches about 230F, turn the mixer on medium-high speed until stiff peaks form. Continue heating sugar mixture to 240F. (The goal is to have the egg whites to stiff peaks and sugar mixture to 240F at the same time.)
When sugar mixture reaches 240F, remove from heat. With the mixer running on low speed, gradually drizzle sugar mixture into whipped eggs (see note).
Increase mixer speed to medium-high and beat mixture until stiff and glossy, about 10 minutes. Add vanilla and mix to combine.
Pipe or spoon marshmallow cream onto the bottoms of the remaining graham cookies. Using a kitchen torch (see note), carefully toast the meringue. You can do this before or after you sandwich the cookies. I do it before, so aaall that marshmallow is toasty.To save my hands from getting burned, I place the cookie on top of a drinking glass, then rotate the glass to toast the marshmallow cream with my hand safely away from the flame.
Sandwich marshmallow cookies with ganache cookies.Enjoy!
Notes
Note on graham flour: Usually I can provide substitutions, but the graham flour is really necessary for your cookies to be like the graham cracker portion of a s'more. You may also see it packaged as "whole wheat pastry flour." If you can't find it in your local grocery store, you can find it [here].Note on agave: I use agave because I have it on-hand and prefer it over corn syrup. If you prefer, you can substitute light corn syrup.Note on working with sugar syrup: Be very careful when working with sugar syrup! If it gets on your skin, it will stick and could cause serious burns. When pouring the syrup into the mixer bowl, don't worry about scraping out every bit of the syrup. Just pour in everything that you can and focus on not getting the syrup on yourself.Note on cookie scoop: I use a large cookie scoop (about 3T volume) to portion out my cookies so they're all uniform in size (and my hands stay a lot cleaner). I really like the one that I use: link [here]. Note on using silpat: I use silpats (like this one [here]) when baking, which makes the cookies brown up a little slower. If you're lining your pans with parchment (or just greasing them), your cookies will likely be done a minute or so sooner.Note on toasting meringue: For some recipes you can use your oven's broiler to toast things, but I don't suggest it in this case. A kitchen torch really is the tool for the job for this one. My kitchen torch is so old I don't even know what kind it is, but this one (link [here]) online has great reviews if you're in the market for one. Otherwise, you could always opt to leave the marshmallow untoasted.