Directions
Tip: Macarons can be finicky, so don't get frustrated if the first attempt doesn't yield the perfect confection you buy from a bakery. Use aged egg whites (crack them and leave them exposed for a day or two). Once you've piped the batter onto the baking sheets, lightly rao the baking sheets against the counter just before putting them in the oven, to ensure that you get those famous macaron "feet."
To make macarons: Preheat the over to 350ºF [180ºC]. Line two baking sheets with parchment paper (or Silpat baking mats, if you have them). Fit a large pastry bag with a ½ in [12 mm] plain tip (or set a 1 gl [3.75 L] zip top bag inside a large cup or small bowl so it's standing up).
Using a food processor, blend together the confectioners' sugar, almond flour, hazelnut flour, and cocoa powder until fine and combined, about 30 seconds.
In the clean, dry bowl of a stand mixer fitted with the whisk attachment (or in a large bowl using a hand mixer fitted with whisk beaters), beat the egg whites on low speed until frothy (you will see small bubbles start to form) about 1 minute, then increase the speed to medium-high and beat until soft peaks form. Gradually add the superfine sugar and beat until firm peaks form, 3 to 4 minutes.
Using a rubber spatula gently fold the flour mixture into the egg white mixture in four additions until just combined. With the final addition, stop folding when there are no more traces of the egg white, being careful not to overmix.
Transfer the batter to the pastry bag or zip-top bag. (If using a zip-top bag, push all the batter toward one bottom corner, cut off the opposite bottom corner of the bag and, pushing out all the air from the bag, squeeze the batter toward the hole.) Slowly pipe 1 in [2.5 cm] rounds about 1 in [2.5 cm] apart onto the prepared baking sheets. After piping all the rounds, hold a baking sheet by the edges and rap it against the counter to help create the macaron feet, and repeat with the other baking sheet.
Bake for 14 to 16 minutes, or until the tops are domed and firm. Transfer the macarons to a wire rack to cool completely, about 1 hour.
To make the ganache: Place the chocolate in a medium bow. Set aside.
In a medium saucepan, bring the cream and corn syrup just to a boil, stirring frequently. Pour the hot cream mixture over the chocolate. Let the chocolate mixture stand for 3 minutes, then stir with a rubber spatula. Add the butter and stir until combined. Pour the ganache into a shallow glass baking dish and allow it to set at room temperature for 1 hour until it is spreadable. (The ganache can be stored at room temperature in an airtight container for 1 day.)
Find two cookies that are approximately the same size. Spread 1 Tbsp of ganache on the flat of one cookie. Place the second cookie on top of the ganache, flat-side down. Press down gently on the cookie sandwich, and put on a wire rack or plate. Repeat until you have filled all the macarons. Let them rest for at least 30 minutes so the ganache can set. Store in an airtight container at room temperature for up to 3 days.
This recipe is courtesy of Amy Guittard from her Guittard Chocolate Cookbook.