Preheat the oven to 300˚F (150˚C).
In the bowl of a food processor, combine the powdered sugar, almond flour, and ½ teaspoon of salt, and process on 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 whip until stiff peaks form (you should be able to turn the bowl upside down without anything falling out).
Add the vanilla and continue whipping until fully incorporated. Add the food coloring (your choice) 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 fold until combined.
After the last addition of almond flour, continue to fold slowly until the batter is the consistency of lava. Do not overfold.
Transfer the macaron batter into a piping bag fitted with a round tip.
Line two baking sheets with parchment paper.
Pipe the macarons onto the parchment paper in 3,8 cm circles, spacing at least 2,54 cm apart.
Tap the baking sheets on a flat surface 5 times to release any air bubbles.
Let the macarons sit at room temperature for 30 minutes to 1 hour until a skin forms on the surface of the macarons.
Bake the macarons for 17 minutes, until the cookies rise and set. The macarons shouldn’t stick to the parchment paper.
Transfer the macarons to a wire rack to cool completely before filling.