For all their simplicity, macarons can be difficult to make at home. Their light-as-air texture, crisp outer shell, and signature foot rely on good technique. In short, it comes down to how you mix the macaron batter.  Macaron batter is made by folding almond flour and confectioners’ sugar into a whipped meringue with a flexible spatula , and the technique even has its own name: macaronage. Macaronage can be challenging because you want to intentionally deflate some of the air in the batter while still preserving enough bubbles to make your macarons light and airy.  Baking Instructor Elisabeth Berthasavage, host of our  Classic Macarons at Home On-Demand class , has the secret to success: Once there are no visible streaks of almond flour or confectioners’ sugar in the batter, she instructs you to use your spatula to smear the batter up the…