Preheat your oven to 140°C / 120°C fan. Line a large baking tray with baking paper.
Seperate 6 large eggs and whisk on medium speed until they form firm peaks.
With the mixer running on low, add 400g caster sugar one tablespoon at a time. Take your time with this,rushing it will affect the texture.
Once all the sugar is incorporated, turn the mixer to high and whisk for a further 5 minutes until the mixture is thick, glossy and holds stiff peaks.
Add 1 tbsp vinegar or lemon juice and 1 tbsp cornflour and whisk for another 2 minutes.
Spread onto your prepared tray into your desired shape.
Place in the oven and immediately reduce the temperature to 90°C / 70°C fan.
Bake for 2 hours without opening the door.
Turn the oven off and leave to cool completely inside the oven, at least 2 hours or overnight.
