Vegan Lemon Souffle

Chill the aquafaba in the refrigerator until very cold. Preheat the oven to 190°C (375°F) with a baking sheet inside on the middle rack. Grease four 180ml ramekins generously with vegan butter, then coat with caster sugar, tipping out any excess.

Whisk the cornstarch into 60ml of the coconut milk in a small bowl until completely smooth. Combine the remaining coconut milk, 80g of the caster sugar, lemon juice, lemon zest, vanilla extract and salt in a small saucepan over medium heat, stirring until the sugar dissolves.

Pour the cornstarch slurry into the warm coconut milk mixture and cook over medium heat, whisking constantly, until the mixture thickens to a smooth, pudding-like consistency, about 3–4 minutes. Remove from the heat and press a sheet of cling film directly onto the surface to prevent a skin forming. Cool to room temperature, about 20 minutes.

Beat the chilled aquafaba and cream of tartar in a spotlessly clean bowl with an electric hand mixer on medium speed until foamy, about 2 minutes.

Increase the mixer to high speed and gradually add the remaining 60g of caster sugar, one tablespoon at a time, beating until the meringue holds stiff, glossy peaks, about 8–10 minutes. The mixture should not slide when the bowl is tilted.

Whisk one-quarter of the aquafaba meringue vigorously into the cooled lemon base to lighten it. Add the remaining meringue in two additions, folding gently with a large rubber spatula using a down-through-the-centre-and-up-over motion, rotating the bowl after each stroke — stop as soon as no white streaks remain.

Divide the batter evenly among the prepared ramekins, filling to 5mm below the rim. Run a clean thumb around the inner edge of each ramekin to create a shallow channel, which encourages an even rise.

Place the ramekins on the preheated baking sheet and bake at 190°C until the souffles have risen 3–4cm above the rim and the tops are set with a very slight wobble at the centre, 18–20 minutes. Do not open the oven door before 16 minutes.

Remove from the oven and serve immediately — souffles begin to deflate within 2–3 minutes.