Rich and flavorful walnuts replace the traditional almonds in these French macarons, with a deep, chocolate-y flavor, and a buttery salted caramel filling! These delicious little pastries are almost a cross between a cookie and a candy, and they're sure to be your new favorite treat! (Naturally gluten-free.)
Sift the ground walnuts, powdered sugar, and cocoa powder together. (Re-process and re-sift, if necessary.)
Place the egg whites in a large mixing bowl, and add the cream of tartar. Whip the egg whites, on medium-high speed, until fluffy. Slowly add in the superfine sugar, while whipping. When all the superfine sugar has been added, turn the speed up to high and continue to whip until stiff.
Add the ground walnut/powdered sugar/cocoa mixture, all at once, and fold until the mixture drops from the spatula in one long ribbon. Transfer to a piping bag fitted with a large round tip.
Pipe the batter onto parchment-lined baking sheets, in 1 1/2-inch circles. Set them out to dry for 45 minutes to an hour, or until a thin, dry membrane has formed on the surface of the macarons.
Preheat the oven to 400 degrees F. Place the macarons in the hot oven. Turn the oven temperature down to 300 degrees F, and bake for 18 minutes (do not brown). Allow the macarons to cool completely on the baking sheets.