01 - Line baking sheets with parchment paper or silicone macaron mats. Fit a piping bag with a ½-inch round tip.
02 - Sift almond flour and powdered sugar into a large bowl. Discard any coarse bits that won't pass through the sieve.
03 - In a clean, grease-free bowl, beat egg whites until foamy. Add cream of tartar, then gradually incorporate granulated sugar. Continue beating until stiff, glossy peaks form.
04 - Gently fold the sifted dry mixture into the meringue in thirds. Use a spatula to press batter against bowl sides until it flows in thick ribbons and you can draw a figure 8 without it breaking.
05 - If using, add gel food coloring and fold until evenly combined. Avoid liquid coloring.
06 - Transfer batter to piping bag. Pipe 1–1½ inch circles onto prepared sheets, spacing them 1½ inches apart.
07 - Firmly tap baking sheets on counter multiple times to release trapped air. Use a toothpick to pop any visible bubbles on surface.
08 - Let piped shells rest uncovered at room temperature for 30–60 minutes until a skin forms—they shouldn't stick to your finger when lightly touched.
09 - Preheat oven to 300°F. Bake one tray at a time for 12–15 minutes, rotating halfway. Shells are done when feet have formed and they lift cleanly from parchment.
10 - Let shells cool completely on baking sheets before removing to prevent cracking.
11 - Beat butter until creamy. Blend in powdered sugar, vanilla, salt, and 1 tablespoon milk. Add more milk as needed to achieve smooth, pipeable consistency.
12 - Pair similarly sized shells. Pipe a dollop of buttercream onto flat side of half the shells, then gently press remaining shells on top to sandwich.
13 - Refrigerate assembled macarons in an airtight container for 24 hours before serving. Bring to room temperature before enjoying for optimal texture.