Preheat the oven to 125C/250F/Gas ½.
For the mini pavlovas, place the egg whites in the bowl of a large food processor with a whisk attachment (make sure the bowl is scrupulously clean). Whisk until soft peaks form when the whisk is removed. Gradually whisk in the sugar until the egg whites are firm. Fold in the cornflour and vinegar.
Spoon the meringue into small nest shapes and place in the oven for 10 minutes. Reduce the heat to 100C/200F/Gas ¼ and cook for an hour. Leave in the oven overnight to cool completely.
For the vanilla cream, place the cream and vanilla seeds in a large bowl and whisk until soft peaks form when the whisk is removed. Set aside.
For the strawberry sauce, place the strawberries into a food processor with the icing sugar and lemon juice. Blend to a purée and then pass through a fine sieve.
To serve, put the quartered strawberries in a bowl and stir in the strawberry sauce. Place the meringue nests onto serving plates and spoon the cream on top. Top with the strawberries in the sauce along with some fresh raspberries. Garnish with mint leaves and a dusting of icing sugar.