Gather all ingredients in one place to ensure you have everything ready before starting this recipe.
In a clean mixing bowl, combine egg whites and cream of tartar; whip until soft peaks form before gradually adding granulated sugar until stiff peaks develop.
Sift together almond flour, powdered sugar, and cocoa powder into another bowl; gently fold into meringue until fully incorporated without deflating.
Transfer batter into a piping bag with a round tip; pipe small circles onto parchment-lined baking sheets while ensuring equal spacing between them.
Place trays in preheated oven on an AirBake insulated baking pan; bake until set and firm to touch without cracking.
Heat heavy cream until just simmering then pour over chopped milk chocolate and Nutella; mix until smooth then let cool slightly before assembling macarons.