Preheat the oven to 150C/300F. Lightly grease a Swiss roll tin and line with parchment paper. First, make the meringue. In a large clean bowl, whisk the egg whites to form stiff peaks. While still beating, gradually add the sugar bit by bit to give a stiff and glossy mixture. Add the vinegar, cornflour and vanilla extract and fold in gently.
Spread the meringue mixture out evenly into the prepared tin and sprinkle over the hazelnuts in a thin even layer. Bake for 20 minutes before reducing the temperature to 110C/230F. Cook for another 25-30 minutes, until lightly golden and springy to touch.
Remove meringue roulade from the oven and leave in the tin for 15 minutes to cool a little. Lay a large piece of parchment paper, just bigger than the roulade, out on a work surface.
Carefully tip the meringue roulade top-side down onto the paper and peel off the paper lightly stuck to the bottom. Leave to cool completely. Softly whip the cream and spread it over the cooled roulade. Scatter almost all of the raspberries over the top, reserving some for decoration. Starting at one short edge, use the parchment paper to gently lift and roll the roulade away from you until you get to the end.
Carefully transfer the meringue roulade to sit seam side-down on a large serving platter. Scatter over the reserved raspberries and decorate with fresh mint sprigs. Serve straight to the table and cut into slices to serve on individual plates.