French Macarons with Vanilla Buttercream

Line two baking sheets with parchment paper or silicone baking mats.

Sift the almond flour and powdered sugar together into a bowl, discarding any large pieces that don't pass through the sieve.

In a clean, grease-free bowl, whip the egg whites on medium speed until foamy, then gradually add the sugar in three additions, continuing to whip until stiff, glossy peaks form.

Add a few drops of food coloring if using, and whip briefly to combine.

Sift the almond flour mixture over the meringue in two additions, folding gently with a rubber spatula after each addition.

Continue folding (macaronage) - scraping from the bottom up and pressing the batter against the side of the bowl - until the mixture flows in a slow, wide ribbon and settles back into itself within about 10-15 seconds. Stop as soon as you reach this consistency.

Transfer the batter to a piping bag fitted with a round tip. Pipe 3.8cm circles onto the prepared baking sheets, holding the bag straight up and about 1cm above the surface.

Tap the baking sheets firmly on the counter several times to release any trapped air bubbles.

Let the piped shells rest at room temperature for 20-30 minutes, until the tops are dry to a light touch and no longer sticky.

Preheat the oven to 150°C (300°F) while the shells rest. Bake one tray at a time on the middle rack for 15-18 minutes, until the shells lift cleanly off the parchment.

Let the shells cool completely on the baking sheet before removing.

For the buttercream, beat the softened butter until pale and fluffy, then gradually add the powdered sugar, vanilla extract, and a splash of milk, beating until smooth and pipeable.

Match the cooled macaron shells by size, then pipe a small amount of buttercream onto half the shells and sandwich with the remaining shells.

Refrigerate the filled macarons in an airtight container for at least a few hours, or ideally overnight, to mature before serving.