4 medium egg whites
225g Chelsea Caster Sugar
1 tsp cornflour
1/2 tsp white wine vinegar
1/2 tsp vanilla essence

Preheat the oven to 150ºC / 140ºC fan / 300ºF / GM 2.
Line a large baking tray with baking paper, and draw round a dinner plate (20cm-ish circle) in the centre of the paper.
Place the egg whites in a clean, grease-free bowl and whisk them until stiff and dry.
Add the sugar, a spoon at a time, whisking until the mixture is smooth, glossy and holds stiff peaks.
Gently fold in the cornflour, vinegar and vanilla with a large metal spoon.
Spoon the mixture onto the baking paper. With the back of the metal spoon, spread it to just within the circle, making decorative swirls, leaving a shallow dip in the centre.
Bake for 1hr until the meringue base and sides are crisp. Leave to cool on a cake rack – cracking is totally normal as it cools.