CHOCOLATE-HAZELNUT MACARONS

Steps:

• Grind the nuts: Pulse the blanched hazelnuts in a food processor until finely ground. (Don't walk away; if you overprocess, you'll have hazelnut butter.) Transfer to a bowl and repeat with the almonds.
• Mix the dry ingredients: Combine 3/4 cup of the ground hazelnuts and 1 cup minus 1 tablespoon of the ground almonds in a large bowl. Sift in the cocoa powder and confectioners' sugar.
• Make the meringue: Whisk the egg whites and granulated sugar in a heatproof bowl set over a saucepan of simmering water. (Don't let the bowl touch the water.)
• Continue whisking until the sugar is dissolved, about 2 minutes. (If you can still feel the sugar, keep whisking.) Turn off the heat but leave the water in the saucepan.
• Using a rubber spatula, transfer the egg white mixture to the bowl of a stand mixer fitted with the whisk attachment.
• Beat on medium-high speed until stiff, glossy peaks form, 5 to 6 minutes. (If you turn the bowl over, the whites shouldn't move.)
• Finish the batter: Fold a few dollops of the meringue into the dry ingredients with a rubber spatula until incorporated. Gently fold in the rest until smooth and fluffy, scooping from the bottom of the bowl to the top.
• Pipe into rounds: Line 2 baking sheets with parchment paper. Fit a pastry bag with a 1/2-inch plain tip and fill with the batter; press out the air. Pipe the batter into 1-inch rounds on the baking sheets, about 1 inch apart.
• Rest and bake: Tap the baking sheets on the counter a few times to remove any air bubbles.
• Let sit at room temperature until slightly dry, 15 to 30 minutes.
• Position racks in the upper and lower thirds of the oven; preheat to 350 degrees F.
• Bake 12 to 14 minutes, or until you can slide a spatula underneath the cookies, switching the position of the pans halfway through. Pull the parchment and cookies off the pans; cool.
• Make the filling: Meanwhile, bring the water in the saucepan back to a simmer. Put the chocolate in a heatproof bowl and set it over the water.
• Stir with a rubber spatula until the chocolate is almost completely melted. Remove the bowl from the pan.
• Heat the heavy cream in a saucepan until simmering. Stir the warm cream and praline paste into the chocolate.
• Fold in the butter, salt and chopped hazelnuts. Let the filling cool until spreadable, about 15 minutes.
• Sandwich the cookies: Spread the filling on half of the cookies with the back of a spoon and sandwich with the remaining cookies. Refrigerate the macarons, wrapped tightly in plastic wrap, for up to 1 week.