French Almond Macaroons
Preheat oven to 300 degrees F. Sift confectioners' sugar into a bowl. Whisk in ground almonds; set aside. Line two baking sheets with parchment paper or nonstick baking mats (such as Silpats), and mark circles using a 1-1/2-inch cookie cutter dipped in flour.
In the bowl of an electric mixer fitted with the whisk attachment beat egg whites on medium speed until foamy; add salt. Gradually add granulated sugar 1 teaspoon at a time, until the whites reach medium-soft peaks. Transfer to a large bowl.
Sprinkle half of the sugar-almond mixture over the egg-white mixture. Using a large rubber spatula fold until just incorporated. Add 1/4 teaspoon vanilla and remaining sugar-almond mixture, folding until just incorporated. Firmly tap the bottom of the bowl on a counter or work surface to eliminate any air pockets.
Transfer mixture to a large pastry bag fitted with a 1/2-inch plain tip (such as an Ateco #806). Pipe mixture into marked circles on prepared baking sheet.
Bake, rotating sheets halfway through, until macaroons feel slightly firm to the touch and can be gently lifted off the parchment (the bottoms will be dry), 20 to 25 minutes. Let cool on the baking sheets for 5 minutes, then transfer parchment and macaroons to a wire rack to cool completely. Using a small offset spatula, carefully remove macaroons from parchment. Spread 2 teaspoons buttercream on the flat sides of the half of macaroons; sandwich with the other halves, keeping flat sides down. Refrigerate until firm, about 20 minutes, before serving. Filled cookies can be kept in an airtight container in the refrigerator for up to 2 days.
Strawberry Macaroons Variation
Follow instructions for French Almond Macaroons, adding 4 drops of red food coloring to the egg whites just before you add the sugar-almond mixture (batter will be pink). For the filling, do not increase vanilla, and fold 1/3 cup strained strawberry preserves (3-1/2 ounces) into Swiss Meringue Buttercream after butter has been incorporated. Proceed with the recipe.
Chocolate Macaroons Variation
Follow instructions for French Almond Macaroons, sifting 2 tablespoons Dutch-process coca powder with the confectioners' sugar. For the filling, place 5 ounces finely chopped semisweet chocolate in a bowl. In a small saucepan, heat 1/2 cup heavy cream until it just starts to simmer; pour over chocolate. Let sit for 1 minute; stir until melted. Let ganache stand at room temperature until thick enough to spread. Proceed with the recipe.
Swiss Meringue Buttercream
In the heatproof bowl of an electric mixer set over a saucepan of simmering water, combine the egg whites and sugar. Cook, whisking constantly, until the sugar has dissolved and the mixture is warm to the touch (about 160ºF).
Attach the bowl to the mixer fitted with the whisk attachment. Beat the egg-white mixture on high speed until it holds stiff (but not dry) peaks. Continue beating until the mixture is fluffy and cooled, about 6 minutes.
Switch to the paddle attachment. With the mixer on medium-low speed, add the butter several tablespoons at a time, beating well after each addition. (If the frosting appears to separate after all the butter has been added, beat on medium-high speed until smooth again, 3 to 5 minutes more.) Beat in vanilla. Beat on lowest speed to eliminate any air bubbles, about 2 minutes. Stir with a rubber spatula until frosting is smooth.
Chocolate Swiss Meringue Buttercream Variation
Follow instructions for Swiss Meringue Buttercream, omitting the vanilla extract, decreasing the sugar to 1 cup, and adding 8 ounces melted best quality bittersweet chocolate after the butter has been incorporated (let chocolate cool slightly before mixing in).
These elegant cookies, found in nearly every pastry shop in Paris, have a crisp exterior and a slight chewy center.