Make the macarons: In the bowl of a food processor, combine the powdered sugar, almond flour, and ½ teaspoon of salt, and process on
1. low speed, until extra fine. Sift the almond flour mixture through a fine-mesh sieve into a large bowl.
In a separate large bowl, beat the egg whites and the remaining ½ teaspoon of salt with an electric hand mixer until soft peaks form.
Gradually add the granulated sugar until fully incorporated. Continue to beat until stiff peaks form (you should be able to turn the bowl upside down without anything falling out).
1. Add the vanilla and beat until incorporated. Add the food coloring and beat until just combined.
Add about ⅓ of the sifted almond flour mixture at a time to the beaten egg whites and use a spatula to gently fold until combined.
After the last addition of almond flour, continue to fold slowly until the batter falls into ribbons and you can make a figure 8 while holding the spatula up.
1. Transfer the macaron batter into a piping bag fitted with a round tip.