For the roulade
4 large egg whites
250g (9oz) caster sugar, plus a little extra for sprinkling
1 teaspoon cornflour
1 teaspoon white wine vinegar
For the filling
300ml (½pt) double cream
4 tablespoon lemon curd
150g (5oz) raspberries
225g (8oz) strawberries
Preheat the oven to 190°C, 375°F, Gas Mark 5. Line a 33 x 23 cm (13 x 9 inch) Swiss roll tin or roasting tin measured across the base with a large rectangle of nonstick baking paper, snipping diagonally into the corners of the paper then pressing into the tin so that the base and sides are lined.
Whisk the egg whites in a large bowl until stiffly peaking and the bowl can be tipped upside down without the egg whites moving in the bowl. Gradually whisk in the sugar a teaspoonful at a time then continue to whisk for a minute or two until thick. Mix the cornflour and vinegar together then fold into the meringue.
Spoon the meringue into the paper lined tin, ease gently into an even layer. Bake for 10 minutes until well risen and just beginning to colour then reduce the heat to 160°C, 325°F, Gas Mark 3 and cook for 5 minutes or until just firm to the touch and beginning to crack.
Put a teacloth on to the work surface, cover with a sheet of nonstick baking paper and sprinkle with a little extra sugar. Invert the hot meringue on to the paper, remove the tin and leave to cool for 1-2 hours.
To finish, peel off the lining paper from the meringue. Whip the cream until it forms soft swirls then spoon over the meringue. Spoon the lemon curd on top then sprinkle with the red berries. Roll up the meringue, starting with one of the narrowest edges, using the paper and teacloth to help. Carefully transfer to a serving plate and remove paper and teacloth. Serve cut into thick slices with extra berries, if liked.
Tip: This dessert can be kept in the fridge for up to 2 days. Freeze on the same day, wrap carefully and make sure it doesn't get squashed in the freezer. Defrost at room temperature for about 1 hour, then decorate with the lemon curd and berries.