Preheat the oven to 110 C. Line a baking tray with baking parchment and using a large dinner plate as a guide, draw a circle with pencil onto baking parchment. Set aside.
Using a handheld electric mixer, start beating the egg whites on low speed, until they start to form stiff peaks. Increase the speed to medium/ high and begin to add 250g of caster sugar, 1-2 tbsp at the time until the meringue looks glossy.
Add 1 tsp of cornflour or arrowroot powder, 1 tsp of white vinegar and 1 tsp of vanilla and whisk again. Spread the meringue inside of the circle creating a small well in the centre. Bake in the oven for 1.5 hour, turn off the heat and let the meringue cool off completely inside of the oven.
In a meantime, mix 200 g of fresh strawberries with 1 tbsp of icing sugar and add it to the food processor or blender and blitz until smooth. Push the mixture through a sieve into a small jug.
When the meringue is cool, whip 300 ml of double cream with 1 tbsp of icing sugar. Top the meringue with whipped cream and strawberries and drizzle with strawberry coulis.
Use metal or glass bowl rather than plastic (they're easier to keep clean and grease-free)
Make sure to add sugar gradually. If you add it all too quickly, the structure will collapse!
Frozen, defrosted egg whites will work well in this recipe
Unfilled meringue can be frozen and stored until you are ready to top it up with cream and strawberries