Special equipment: candy thermometer, 2-inch round cookie cutter
Make the graham crackers: In a stand mixer fitted with a paddle attachment, beat together butter and sugar until lightened in color, then fold in egg until combined. In a separate bowl, combine dry ingredients. In another bowl, whisk together molasses, honey, and milk. Add half the dry ingredient mixture to butter and sugar and beat to combine, then add half molasses mixture, scraping the bowl after each addition, and repeat with remaining dry and wet ingredients. Chill dough for at least 1 hour. The dough will very soft.
Preheat oven to 350 degrees. On a heavily floured surface, roll dough to ¼-inch thick. Using a 2-inch round cookie cutter, cut 24 circles out of the dough and place on parchment-lined cookie sheets. Bake for 8-10 minutes.
Make the marshmallow filling: In a small bowl to which the gelatin had been added, slowly stream ¾ cup water and whisk mixture to smooth any lumps. Set aside. In a small saucepan over medium heat, combine sugar and corn syrup with enough water to achieve the consistency of wet sand. Using a candy thermometer, cook the mixture to 260 degrees. Meanwhile, in the bowl of stand mixer, whisk egg whites by hand (the whisk attachment likely won’t reach the small volume of egg whites) until frothy. Once sugar reaches 260 degrees, slowly stream into frothy egg whites. Set the mixer fitted with whisk attachment to high and whip until it has quadrupled in volume. Add gelatin and continue to whip mixture until it forms stiff peaks. Add vanilla.
Working quickly while the filling is still slightly warm, pipe or spoon marshmallow onto graham cracker and top with second cracker. Repeat.
Make the ganache: In a medium bowl over low heat, heat cream just until it starts to come to a boil. Add chocolate chips and whisk until combined.
To assemble: Position Moon Pies on wire rack over a baking sheet. Pour ganache over pies, and using a knife, spread evenly over the tops and sides. Allow to set before serving.