• 1 3/4 cups confectioners’ sugar
• 1/2 cup (2 ounces) slivered or sliced blanched almonds
• 1/2 cup (2 ounces) roasted pistachio nuts, salted or unsalted
• 4 large egg whites, at room temperature
• 1/4 teaspoon cream of tartar
• 1/2 cup sugar
• 1 teaspoon almond extract
• 6 drops green food coloring, or enough to tint the batter a soft green

Directions:

For the cookies: Preheat the oven to 350 degrees (to allow for a thoroughly heated oven). Line the bottoms of 2 baking sheets with parchment paper or silicone liners. 

Place the confectioners’ sugar in the bowl of a food processor and process with several short pulses to aerate. Add the almonds and pistachios, and process for about 2 minutes, until the nuts are finely ground, stopping the motor every so often to break up any clumps that form in the bottom of the bowl. Transfer to a large bowl, breaking up any clumps. 

Beat the egg whites and cream of tartar in the bowl of a stand mixer or hand-held electric mixer on medium-low speed until frothy. Increase the speed to medium-high and beat until soft peaks form; then, still beating, gradually add the granulated sugar. Beat until the egg whites are glossy and voluminous and form stiff peaks. Reduce the speed to low; add the almond extract and the food coloring, and mix just to incorporate. 

Use a spatula to fold half of the beaten egg whites into the sugar mixture to partially combine and lighten it. Fold in the remaining beaten egg whites until no white streaks remain and they are completely incorporated; do not overmix. 

Fit a large pastry bag with a 3/8-inch (1-centimeter) plain tip. Spoon the batter into the bag. Holding the pastry bag upright, pipe blobs of batter about 1 inch in diameter, spaced 1 inch apart on the prepared baking sheets; you should be able to fit 36 cookies on each sheet. Let sit uncovered on a flat surface at room temperature for 30 to 60 minutes. The tops will look smooth and lose their shine, and the batter will spread slightly. 

Bake one sheet at a time on the middle rack for about 12 minutes or until the tops feel firm and crisp when lightly touched. If using a parchment paper liner, allow to cool for a couple of minutes, then peel the cookies from the paper by pressing them off from the underside. Or, to ensure that the cookies release easily, as soon as you remove the baking sheet from the oven, carefully lift the parchment one end at a time and sprinkle a total of about 2 tablespoons of water under the paper, moving the paper around a little to distribute the moisture more evenly. The steam will loosen the cookie bottoms from the paper. After 3 minutes (and no longer), lift the paper liner from the baking sheet and peel the cookies from the paper. If any of them stick, slide a thin metal spatula under the bottoms to loosen them. If using a silicone liner, let the macarons rest on the lined baking sheet for 10 minutes, then peel off the macarons. Transfer the macarons to a wire rack to cool. Repeat to use all of the batter; you should end up with at least 100 bite-size cookies. 

Meanwhile, make the filling: Beat the butter, confectioners’ sugar, lemon zest, lemon juice and almond extract in the large bowl of a stand mixer or hand-held electric mixer on medium-low speed until smooth. Mix in the food coloring, if using. 

When ready to fill, turn half of the cooled macarons bottom side up. Use a small rounded knife to spread about 1 rounded teaspoon of the filling over each cookie bottom, or use the pastry bag and tip to pipe the filling onto the cookies. Press the flat bottoms of the remaining cookies onto the filling to create about 50 small macaron sandwiches. (You may have a little filling left over.) Serve, or cover and store at room temperature or in the refrigerator for up to 3 days. 

Piping do’s and don’ts:

To pipe out macaron batter, use one hand to hold the pastry bag twisted and closed at the top and the other hand to guide the tip. Hold the bag straight up and down, with the tip close to the parchment paper or silicone liner. Use your top hand to squeeze out a round blob of batter 1 inch in diameter. Don’t try to draw a circle at fill it in; the results are more likely to be irregular. You might find it helpful to draw 1-inch circles on the parchment paper as guides; turn the paper over and pipe onto the non-penciled side. You’ll have no trouble seeing the guide lines.