Line 3-4 baking sheets with parchment paper.
Grind the granulated sugar in a food processor and set it aside.
Process almond flour and powdered sugar together until smooth and lump-free.
Wipe the bowl of a stand mixer with a bit of vinegar. Add egg whites, cream of tartar, and salt. Whisk on medium-high speed until frothy.
Gradually add the previously ground granulated sugar while whisking, until a glossy, stiff meringue forms. Add vanilla and food coloring towards the end.
Add a third of the almond flour and powdered sugar mix to the meringue, gently folding it in with a spatula using a circular motion. Once partially mixed, add the remaining dry ingredients.
Continue folding until well mixed. Rub the spatula through the batter to eliminate large air bubbles.
Check the batter consistency – it should slowly run off the spatula in a continuous ribbon. Transfer the batter to a piping bag.
Pipe 1-inch circles onto the prepared baking sheets.
Tap the sheets on the counter to remove air bubbles, using a toothpick to pop any large ones.
Let the macarons rest at room temperature for 1.5-2 hours.
Preheat the oven to 300°F (150°C).
Bake for 10-11 minutes.
Once cooled, fill with buttercream or cream cheese frosting.