Hazelnut Macarons with Gianduja Ganache

Ideally, these cookies are made with aged egg whites. To age your whites, simply separate your eggs a day or two before you make the cookies. Put the whites in a container, cover them with plastic wrap, poke a few holes in the plastic to let them dry out a little, and keep them refrigerated. Be sure to let them come to room temperature before you use them. The other trick to these cookies is to make them a day before you plan to serve them: their crisp shells will absorb moisture from the filling, making them extra moist and chewy.

Ingredients for cookies:

• 2 cups (7 ounces) ground hazelnut meal
• 2 cups (9 ounces) confectioners’ sugar
• 4 egg whites, at room temperature
• ½ cup (3 ½ ounces) granulated sugar

Ingredients for the filling:

• ¾ cup hazelnuts, toasted and skinned
• 4 ounces Theo 45% Milk Chocolate, melted
• ¼ cup heavy cream

Instructions (makes 3 dozen filled cookies):

1. Preheat the oven to 250 degrees F. Line 2 baking sheets with parchment paper and set aside.
2. Spread the hazelnut meal on a third baking sheet. When the oven is hot, bake the meal for 30 minutes to dry it out. Set aside to cool.
3. When the hazelnut meal has cooled, put it in the bowl of a food processor, add the confectioners’ sugar, and grind for about 1 minute, stopping to pulse 2 or 3 times to get what’s climbing the sides to fall. Check that the meal isn’t clumping, then grind again for another minute, pulsing 2 or 3 times. Sift the mixture through a fine mesh strainer. If there’s more than a tablespoon of nut meal left in the strainer, grind this portion again. If there’s less than a tablespoon left, just discard it.
4. In the bowl of a stand mixer fitted with the whisk attachment, whisk the egg whites on medium speed until completely frothy. Gradually add the granulated sugar while the mixer is running. When all the sugar has been added, increase the speed to medium-high and whip the whites until they’re stiff and glossy.
5. Take the mixing bowl off the stand mixer, add half the hazelnut mixture to the egg whites, and, using a spatula, fold them together. Add the remaining hazelnut mixture and fold together until completely mixed. The batter will be very stiff. You want to continue folding it until the batter softens and drips off your spatula in a long ribbon, rather than falling off in clumps. A drop of batter should take about 30 to 45 seconds to reincorporate into the rest of the mixture.
6. Scrape the batter into a piping bag (or a heavy duty resealable plastic bag with a corner snipped off) fitted with a ½-inch round tip. Pipe 1-inch kisses of batter at least 1 inch apart onto the prepared baking sheets. Hold the bag perpendicular to the baking sheet with the tip about ½ inch off the surface of the paper. Squeeze out a bit of batter, and stop squeezing before you lift the bag away. This will keep the kiss flat—you want the tail you leave behind to be as small as possible.
7. When you’ve filled the first baking sheet, tap it firmly on the countertop to flatten the tails and release air bubbles trapped inside. Repeat with the second baking sheet.
8. Leave the baking sheets on the countertop, uncovered, until a skin forms on top of the cookies, about 30 to 60 minutes depending on the temperature and humidity of your kitchen. While the cookies are resting, adjust the oven racks to the top and bottom thirds of the oven, and preheat it to 280 degrees F.
9. To bake, place 1 baking sheet on each rack and bake for 7 minutes. Rotate the pans top to bottom and front to back, and bake for about another 7 minutes. The macarons will have developed a “foot” on the bottom, and be smooth and slightly shiny with no cracks. You can remove a pan from the oven to see if they will lift from the parchment, or just gently press on a cookie—if it barely moves or doesn’t move on its foot, it’s ready. If in doubt, bake for another minute.
10. Let the cookies cool completely on the baking sheets while you make the ganache filling.
11. To make the filling, grind the hazelnuts in a food processor until they become hazelnut butter (it won’t be perfectly smooth, but that’s OK). Transfer the butter to a medium bowl, add the melted chocolate, and stir to blend. Add the cream and stir to incorporate. If the filling is very liquid, let it sit at room temperature until spreadable.
12. When the cookies are cool, turn half of them upside down. Put a teaspoon of filling on each of the upside-down cookies. Place another cookie on top, and gently press them together (it’s easiest to almost screw them together) until the filling spreads all the way out to the edge.
13. Cover the macarons and refrigerate for 24 hours. Bring them back to room temperature before serving.