Preheat your oven to 110°C and line two baking sheets with parchment.
Separate 6 eggs into yolks and whites (reserve the yolks for crème anglais).
Whisk the whites until they hold firm peaks, then add 300g caster sugar one tablespoon at a time with the mixer still running (this takes around 8 minutes).
The mixture should be thick, glossy, and feel smooth between your fingers.
Fold in 1 tsp white wine vinegar and 1 tsp cornflour.
Drop large freeform mounds onto the trays - roughly hand-sized - and pull up rough peaks with the back of your spoon.
Bake for 1 hour 15 minutes, then turn the oven off and leave them inside with the door closed for at least 1.5 hours.
They’re ready when they lift cleanly off the parchment and sound hollow when tapped.
