1. Line a baking sheet with baking parchment and brush very lightly with oil.
2. Blend the egg white and 30 ml/2 tbls of the water until smooth, then stir in the remaining water. Whisk until very stiff.
3. Combine the cornflour and vinegar and whisk into the egg white with the sugar. Spread in an even circle 2.5 cm/1 in thick on the parchment.
4. Cook in the centre of a cool oven at 140°C/275cF/Gas mark 1 for 1 hour. Turn off the oven and leave the Pavlova to cool in the oven.
5. Carefully peel the parchment from the Pavlova and place it on a serving dish.
6. Whip the cream until stiff. Spread on the Pavlova, leaving a 2.5 cm/1 in border all round. Hull the strawberries and pile on to the cream. Serve at once.