Sift together almond flour and powdered sugar into a large bowl for the macaron shells.

In a separate bowl, beat egg whites until frothy. Heat granulated sugar and water until syrup reaches 244°F (118°C).

Slowly drizzle sugar syrup into egg whites while mixing on low, then increase to high and whip until glossy and stiff peaks form.

Gently fold a small portion of meringue into almond mixture, then add remaining meringue and fold until batter flows like lava.

Pipe small rounds onto parchment-lined baking sheet, tap to release air bubbles, and bake at 320°F (160°C) for 12-14 minutes.

Heat heavy cream with vanilla until simmer, pour over chopped white chocolate, and let sit for a minute before stirring until smooth.

Whip cooled ganache until creamy, pair macaron shells by size, and pipe ganache onto one shell before sandwiching with another.

Transfer filled macarons to an airtight container and refrigerate for at least 1 hour or overnight before serving.