Make the chocolate macaron shells:

1. Line one or two baking sheets with silicone mats. Set aside.
2. Place a sieve over a bowl set on a scale. Sift the almond flour until you reach 130 grams, discarding any large pieces. Repeat with confectioners’ sugar and cocoa powder. Whisk together until very well combined, then set aside.
3. Add the egg whites and white sugar to the bowl of a stand mixer. Whisk by hand to combine, then attach the whip attachment. Beat eon low speed until soft peaks form, increase to medium until medium peaks form, then increase to high. Beat until stiff, glossy peaks develop. Add gel food coloring and mix until just combined.
4. Remove the bowl from the mixer. Place a sieve over the meringue and sift in the dry mixture.
5. Gently fold the dry ingredients into the meringue, being careful not to deflate it. The batter is ready when it flows in smooth ribbons off your spatula. It should fall continuously, without drizzling off too quickly If it is coming off in large V shaped chunks it needs to be folded more. Use the figure eight test to confirm the right consistency: If you can lift some batter up and use it to draw several figure 8’s without the stream breaking, it is ready.
6. Transfer the batter to a piping bag fitted with a medium round tip. Pipe 1 to 1 ½-inch circles onto the prepared baking sheets, holding the bag straight above the pan and perpendicular to baking sheet.
7. After you’ve piped all the macarons, tap the baking sheet firmly on the counter several times to remove air bubbles. Use a toothpick to pop any remaining bubbles.
8. Preheat the oven to 300°F. While it heats, allow the macarons to sit until a thin “skin” forms. This can take anywhere from 8 minutes to an hour, depending on humidity. They are ready when you can lightly touch the tops without batter sticking to your finger. Keep checking them periodically to see if they have formed a skin.
9. Bake for 15-20 minutes. Check at 15 minutes, then continue baking one minute at a time until the tops are firm and do not wiggle at the base. Cool completely on the silicone mat before removing.
10. Once cooled, gently peel all the macaron shells off the mats and set aside.

Make the hot chocolate buttercream filling:

1. Add butter and marshmallow fluff to a large mixing bowl and beat with an electric hand mixer until fluffy, about 2 minutes. Add in the confectioners’ sugar, hot chocolate powder, and vanilla. Beat again until smooth, well-combined, and creamy.

Assemble the hot chocolate macarons:

1. Melt the chocolate using a double boiler or microwave.
   • On the stove: Bring 2 inches of water to a low simmer in a saucepan over medium-low heat. Then, turn the heat to low and place a medium heatproof bowl on the mouth of the pot. Make sure that there is a gap of a few inches in between the bottom of the bowl and the water (You can also place a bowl on a steamer attachment on top of your pot). Add the chocolate and stir constantly as it melts. Stir until the chocolate is completely smooth and melted. This should take a few minutes.
   • In the microwave: Place a medium heatproof bowl of chocolate into the microwave and microwave in 30 second intervals. Remove the bowl at each interval and stir well. Repeat until the chocolate has completely melted. Stir until completely smooth.
2. Drizzle melted chocolate over half of the macaron shells and sprinkle with dehydrated mini marshmallows. Let them set until firm.
3. Transfer the hot chocolate buttercream to a piping bag fitted with a round tip. Pipe a generous amount onto the undecorated shells. Top each one with a decorated shell of similar size.

4. Refrigerate the filled macarons overnight to allow the shells and filling to meld together for the best texture and flavor.