For the Macarons-Preheat oven to 300, line two baking sheets with parchment paper.
Sift together almond meal, powdered sugar, and cocoa powder. Once sifted, sift for a second time, set aside.
In either the bowl of a stand mixer or with a hand mixer, beat egg whites and granulated sugar on low for 2 minutes, then turn speed to medium and beat for 2 minutes, then beat on high for another 2 minutes. Egg whites should hold stiff white peaks.
Fold egg whites into the sifted dry ingredients, folding under, until well combined.
Line a cup with a Ziplock bag (you'll use this as a piping bag), then use a spatula and pour the batter into the bag. Remove the bag from the cup, cut a little hole off one corners and then in a circular motion squeeze quarter sized circles, an inch or so apart on the parchment lined baking sheets.
Sprinkle half the cookies with sprinkles. Let cookies sit for 30 minutes, then bake for 6-8 minutes until you see the cookies rise a little and the feet form, remove from oven and allow to cool, do not over bake.
While the cookies are cooling, make the nutella buttercream. Start by creaming the butter for a minute, then add the nutella and milk, beat for a minute on medium speed, then slowly add the powdered sugar until the buttercream forms. You can use it immediately or store it in the fridge (you'll need to let it come to room temperature before using because it will turn hard when cold).
To assemble the macarons spread a tsp of nutella buttercream on one half of a cookie, top with a cookie with sprinkles, and voila, you have yourself a chocolate nutella buttercream macaroon!
