For the filling:
Soak the gelatine in a little cold water for 10 minutes.
Squeeze it out then place in a small pan with the white wine and let it dissolve over a very gentle heat.
Beat together the egg yolks and sugar until pale and creamy, then stir in the lemon zest and juice.
Slowly fold in the gelatine and wine mixture then set aside to cool.
Heat the oven to 180°C (160°C fan) and line a Swiss roll tin with non-stick baking paper.
For the meringue:
Whisk the egg whites until they form soft peaks then gradually whisk in the sugar until stiff.
Fold in the cornflour until incorporated, then spoon the mixture into the tin.
Bake for 10 -12 minutes, until just firm.
Allow the meringue to cool for a few minutes, then turn out onto a sheet of non-stick baking paper dusted with icing sugar.
Spread over the lemon filling and gently roll up the meringue, using the paper to help.
Carefully transfer onto a serving dish, chill for 1 hour and dust with a little more icing sugar just before serving.