Preheat oven to 320° with rack in lower third. Place almond flour and confectioners’ sugar; pulse until combined. Pass almond mixture through a fine-mesh sieve.

Whisk egg whites and granulated sugar by hand to combine. Beat on medium speed for two minutes. Increase speed to medium-high and beat two minutes. Then beat on high two minutes more. The beaten egg whites will hold stiff, glossy peaks when you lift the whisk out of the bowl. Add vanilla and food coloring, and beat on highest speed 30 seconds. Add dry ingredients all at once. Fold with a spatula from bottom of bowl upward, then press flat side of spatula firmly through middle of mixture. Repeat just until batter flows like lava, 35 to 40 complete strokes.

Rest a pastry bag fitted with a 3⁄8-inch round tip (Ateco #804) inside a tall glass. Transfer batter to bag; secure top. Dab some batter remaining in bowl onto corners of 2 heavy baking sheets; line with parchment. With piping tip ½ inch above sheet, pipe batter into a ¾ -inch round, then swirl tip off to one side. Repeat, spacing rounds 1 inch apart. Tap sheets firmly against counter 2 or 3 times to release air bubbles.

Bake one sheet at a time, rotating halfway through, until risen and just set, 8 minutes. Then open the oven door, allowing the steam to escape, close door and bake for 2 more minutes. Then repeat, open oven door again, close door and bake for the last 2 minutes. Remove from oven and place sheet pan on wire rack. Let cool. Pipe or spread filling on flat sides of half of cookies; top with remaining halves. Wrap in plastic and refrigerate for 24 to 48 hours to allow macarons to meld and soften.