Make the Graham Cookies:

1. Prepare the dough: In a large bowl, whisk together the all-purpose flour, graham flour, brown sugar, baking soda, and salt until well combined. Add the softened butter, honey, milk, and vanilla extract. Using a hand mixer or stand mixer, beat on medium speed until the dough comes together into a cohesive ball, about 2-3 minutes. The dough should be soft but not sticky.
2. Chill the dough: Shape the dough into a flat disk, wrap tightly in plastic wrap, and refrigerate for at least 30 minutes. This makes the dough much easier to roll out and prevents the cookies from spreading too much during baking.
3. Roll and cut: Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper. On a lightly floured surface, roll the chilled dough to about ⅛-inch thickness. Using a 3-inch round cookie cutter, cut out circles and place them on the prepared baking sheets, spacing them about 1 inch apart. Gather scraps, re-roll, and continue cutting until all dough is used. You should get about 24 cookies.
4. Bake: Bake for 10-12 minutes, until the edges are just starting to turn golden brown. The centers may look slightly soft, but they’ll firm up as they cool. Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.

Make the Marshmallow Filling:

5. Bloom the gelatin: Pour ¼ cup of cold water into the bowl of your stand mixer and sprinkle the gelatin evenly over the surface. Let it sit for 5 minutes to bloom (it will absorb the water and become thick).
6. Cook the sugar syrup: In a small saucepan, combine the remaining ¼ cup water, sugar, corn syrup, and salt. Place over medium-high heat and stir until the sugar dissolves. Attach a candy thermometer to the pan and cook without stirring until the mixture reaches 240°F (soft-ball stage), about 7-10 minutes. Watch carefully as it approaches temperature.
7. Whip the egg whites: While the syrup cooks, add the egg whites to the gelatin mixture in your stand mixer bowl. Using the whisk attachment, beat on medium-high speed until soft peaks form, about 2-3 minutes.
8. Combine and whip: With the mixer running on low speed, very carefully pour the hot sugar syrup in a slow, steady stream down the side of the bowl (avoid pouring directly onto the whisk, which can splatter). Once all the syrup is added, increase speed to high and whip for 7-10 minutes, until the mixture is very thick, glossy, and tripled in volume. The bowl should feel barely warm to the touch. Beat in the vanilla extract during the last minute.
9. Pipe the filling: Transfer the marshmallow to a large piping bag or zip-top bag with the corner snipped off. Working quickly before the marshmallow sets, pipe a generous mound of marshmallow onto the flat side of 12 cookies, leaving about ¼ inch border around the edges. Gently press the remaining 12 cookies on top, flat side down, creating sandwiches. Let the assembled Moon Pies sit at room temperature for at least 30 minutes to allow the marshmallow to set.

Coat with Chocolate:

10. Melt the chocolate: Combine the chocolate wafers (or chips) and coconut oil in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each, until completely smooth and melted. Alternatively, melt using a double boiler on the stovetop.
11. Coat the Moon Pies: Place a wire rack over a parchment-lined baking sheet (to catch drips). Using a fork or dipping tool, carefully lower one Moon Pie at a time into the melted chocolate, turning to coat completely. Lift it out, letting excess chocolate drip off, then place it on the wire rack. Repeat with all Moon Pies.
12. Set the chocolate: Let the chocolate coating set at room temperature for about 1 hour, or refrigerate for 20-30 minutes to speed up the process. The chocolate should be completely firm and no longer tacky to the touch.
13. Serve and enjoy: Once the chocolate is fully set, your homemade Moon Pies are ready to enjoy! For the best texture and flavor, let them sit at room temperature for 24 hours before serving – this allows the cookies to soften slightly and all the flavors to meld together beautifully.