With the rack in the middle position, preheat the oven to 350°F (180°C). Butter an 8-inch (20 cm) square baking dish and line the bottom with a sheet of parchment paper, letting the paper hang over two sides.
In a bowl, combine all the ingredients until the mixture sticks together. Lightly press onto the bottom of the prepared dish.
Bake for 12 minutes. Let cool on a wire rack.
Place the chocolate in a bowl.
In a saucepan or in the microwave, bring the cream and honey to a boil. Remove the heat and pour over the chocolate. Let melt for 1 minute without stirring.
Using a spatula, stir until the ganache is smooth. Spread over the crust. Refrigerate while preparing the marshmallow.
In a saucepan off the heat, sprinkle the gelatine over the water. Let bloom for 5 minutes. Add the sugar and heat over medium heat until the gelatin and sugar have melted. Do not boil.
Pour the gelatin mixture into a bowl, then add the honey. Using an electric mixer, whip until semi-stiff peaks form, about 5 minutes. Spread the marshmallow over the ganache. Let rest for 1 hour.
Cut into squares. Using a culinary torch, caramelize the marshmallow. The s'mores squares will keep for 1 week in an airtight container at room temperature.