In a mixing bowl, combine sifted almond flour with powdered sugar and egg whites. Add vanilla powder. Set aside.

Beat the egg whites until stiff peaks form. Meanwhile, make a syrup by heating the water and sugar. Bring to a boil, then heat to 230°F (110°C). Gradually pour the syrup into the beaten egg whites while continuing to whip with a stand mixer. Whip until the mixture cools and forms stiff peaks.

Mix one quarter of the meringue into the batter, then gently fold in the rest with a spatula. This is the macaronage step. The batter should flow in ribbons.

Transfer the macaron batter to a piping bag and pipe small rounds onto parchment paper. Tap the baking sheet. Let them sit for 30 minutes to form a skin, then bake at 285°F (140°C) on the lower rack for 20 minutes.