Using a permanent marker, draw 2-inch circles 1 inch apart on 2 sheets of parchment paper (24 per sheet). Place parchment, marker side down, on 3 rimmed baking sheets.

In a medium bowl, sift together flour and confectioners’ sugar.

In the heatproof bowl of a stand mixer, whisk together egg whites and granulated sugar by hand until frothy. Place bowl over a small saucepan of simmering water. Cook, whisking constantly, until sugar completely dissolves, mixture is warm to the touch, and a candy thermometer registers 160°F (71°C), about 2 minutes.

Carefully return bowl to stand mixer. Using the whisk attachment, beat at high speed until stiff peaks form. Add a small amount of food coloring, beating until desired color is reached. Fold in flour mixture. (Mixture should be thick and slowly but freely fall off the spatula in a “V” shape, and when you drag the spatula through the batter, it should move like lava and slowly come back together.)

Transfer batter to a pastry bag fitted with a medium round piping tip (Ateco #803). Holding piping tip perpendicular to pans, apply pressure to bag, leaving tip stationary, and pipe batter onto drawn circles until batter just reaches drawn circle. Move and lift tip in a quick circular motion as you finish piping each macaron shell to prevent points from forming on top of shells. Firmly tap pans vigorously on counter 5 to 7 times to release air bubbles. Sprinkle with pistachios. Let stand at room temperature until a skin forms on top, 1 to 2 hours. (Batter should feel dry to the touch and should not stick to your finger.)

Preheat oven to 300°F (150°C).

Bake, one pan at a time, until firm but wobbles slightly at the touch. 20 to 25 minutes. Let cool completely on pans.

Remove cooled macaron shells from pans. Turn half of shells flat side up.

Spoon Pistachio Buttercream into a pastry bag fitted with a ¼-inch round piping tip. Pipe a border of buttercream (about a heaping 1 tablespoon or 9 grams) onto shells with flat side up.

Spoon Raspberry Curd into a pastry bag; cut a ½-inch opening in tip. Fill center of buttercream border with curd (about 3 grams each). Gently top with remaining shells, flat side down. (Use light pressure to avoid cracking). Best served same day. Refrigerate in an airtight container for up to 3 days.

In the bowl of a stand mixer fitted with the paddle attachment, beat butter at medium speed until creamy, 2 to 3 minutes. Gradually add confectioners’ sugar, pistachios, and salt, beating until smooth, stopping to scrape sides of bowl. Add a small amount of food coloring; beat until well combined, light, and fluffy, about 2 minutes. Use immediately.

In a medium saucepan, bring raspberries, sugar, and lemon zest and juice to a boil over medium heat, stirring occasionally until sugar dissolves. Reduce heat, and simmer for 5 minutes. Transfer mixture to the container of a blender, and blend until smooth. Strain mixture through a fine-mesh sieve, discarding solids. Return mixture to saucepan, and heat over medium heat.

In a medium bowl, whisk together egg yolks, cornstarch, and salt. Add about one-fourth of hot raspberry mixture to egg yolk mixture, whisking constantly. Whisk egg yolk mixture into remaining hot raspberry mixture in pan. Cook over medium-high heat, whisking constantly , until thickened, 5 to 7 minutes. Remove from heat; whisk in butter 1 tablespoon (14 grams) at a time, until melted and smooth until after each addition. Cover and refrigerate until thick and cold before using, at least 2 hours or up to 1 week.