Measure and sift the almond flour, icing sugar and hot chocolate into a bowl. Set this bowl of dry ingredients aside.
Place your macaron template (if using one) on your baking tray and cover it with a layer of baking paper (or silicone mat). Set this aside also.
Place the sugar, egg powder and egg whites into the bowl of your stand mixer.
Fill a saucepan with about an inch of boiling water and put it on low heat on the stovetop.
Place the bowl of your stand mixer on top of the saucepan to make a makeshift double boiler. Use a whisk to stir the egg whites and sugar over low heat with a whisk until the sugar completely dissolves.
Remove the stand mixer bowl from the heat, and fix it to the mixer. Fix the whisk attachment to your stand mixer. Add the Cream of Tartar to the egg whites and whip the mixture until it forms stiff peaks. The bowl of your stand mixer should feel cool to touch.
Add the salt and vanilla extract, and whip for a further 30 seconds until its all stirred through.
Add half the dry ingredients to the meringue and gently fold it in using a rubber spatula. Then repeat this process with the second half of the dry ingredients.
Next deflate the mixture slightly by spreading it around the sides of the bowl, then scrape it back into the middle. Continue this process until the batter becomes slightly runny. You know it is ready when you can scoop up some with your spatula and it falls off in a ribbon shape. See my blog post for a photo that demonstrates what this looks like.
Transfer the batter to a piping bag that has been fitted with a round nozzle. Pipe the macarons onto a baking tray that has been lined with either a silicone mat or parchment paper.
Once you've piped your macarons, bang the tray on the counter at least 3 times to encourage any air bubbles to rise to the surface. Then inspect the macarons closely and use a tooth pick to pop any air bubbles you can see.
Allow the macarons to sit on the counter until they dry slightly. They will be ready to bake when they look mat and don't feel sticky. This can take anywhere for 20-40 minutes, depending on the weather.
If you have used a printed template as a guide, make sure you remove this from the tray before you bake you bake your macarons.
Bake in the oven at 270 degrees Fahrenheit (130 degrees Celsius) for 17-20 minutes. See notes for how to check if macarons are cooked.
Allow the macarons to cool completely on the baking tray before transferring them to an air tight container.