French Macaron Shells (Italian Meringue Method)

Weigh the almond flour and icing sugar precisely — macarons are a baking formula, not a recipe, and a 5g deviation in a 300g batch will affect the outcome. Pulse them together in a food processor for 30 seconds to break up any clumps and homogenise the particle sizes. Sift through a fine-mesh sieve into a large bowl, discarding any coarse almond particles that won't pass through — these lumpy particles create bumps on the macaron surface. If your almond flour is coarser, re-process and sift again. The tant-pour-tant (equal-weight almond and sugar) should be completely smooth, dry, and fine, like very fine sand. Add the first portion of aged egg whites (approximately half the total egg whites) to the tant-pour-tant and mix with a spatula until you have a thick, paste-like batter. Cover and set aside.

Combine the caster sugar and water in a small, clean saucepan. Heat over medium-high heat without stirring — stirring encourages crystallisation. Fit a candy thermometer or use an instant-read thermometer. While the syrup heats, begin whipping the second portion of aged egg whites with the cream of tartar in the bowl of a stand mixer fitted with the whisk attachment, on medium speed. When the syrup reaches 115°C (239°F), increase the mixer to high speed. When the syrup reaches exactly 118–121°C (244–250°F, soft-ball stage), remove from heat immediately. With the mixer running on high, pour the hot syrup in a slow, thin, steady stream down the inside of the bowl — never directly onto the whisk, which will spin it into sugar threads on the bowl sides. The hot syrup cooks and stabilises the meringue as it is incorporated.

After incorporating all the syrup into the whipping whites, continue beating on high for 8–10 minutes until the meringue reaches firm, glossy peaks and the bowl feels just warm — not hot — to the touch. The Italian meringue should be bright white, very glossy, and hold stiff peaks that curl slightly at the tip. If you lift the whisk and turn it upside down, the peak should hold its shape without drooping. The meringue must cool to around 40°C before you fold it into the almond paste — too hot and it will melt the fat in the almond flour; too cold and it will stiffen and resist folding. The meringue can rest, covered, for up to 10 minutes while you prepare for the macaronage.

Add the Italian meringue to the almond paste in three additions, folding with a wide silicone spatula. The technique is called macaronage: use the flat of the spatula to smear the batter against the side of the bowl in a sweeping motion, rotating the bowl with your other hand. This deliberately deflates the meringue to achieve the correct ribbon consistency. The macaronage is complete when the batter falls from the spatula in a thick, continuous ribbon — draw the spatula through the batter and lift: it should flow back together in 10 seconds, erasing the trace completely. If the trace takes more than 15 seconds to disappear, continue folding. If the batter flows like liquid, you have gone too far. The correct batter moves slowly, like lava, and when a ribbon of it falls onto the surface it sinks back in 8–10 seconds. Most batches take 40–60 fold strokes total.

Pipe the batter onto parchment-lined baking sheets in 3.5 cm rounds, holding the piping bag perpendicular to the sheet at a height of 1 cm. After piping, firmly tap the baking sheet against the counter 5 times to release trapped air bubbles. Burst any bubbles with a toothpick. Let the piped rounds rest at room temperature for 30–60 minutes, until a dry skin forms on the surface — when you touch one lightly with the tip of a finger, it should not stick and should feel slightly tacky but firm. This skin is what forces the expanding air to push out through the bottom during baking, creating the characteristic ruffled feet. Bake at 150°C (300°F) in a convection oven (or 160°C / 320°F conventional) for 13–15 minutes. Rotate the pan at the 7-minute mark. The shells are done when they lift cleanly off the parchment with no resistance.