Preheat the oven to 200℃ (180℃ fan)/400°F/gas mark 6. Line a 26 x38cm (10x15in) swiss roll tin with baking parchment.
Place the pistachios in a food processor or grinder and blitz until very finely ground.
Whisk the egg whites in a large mixing bowl until standing in stiff peaks. Gradually whisk in the sugar a tablespoonful at a time and continue whisking until you have a thick glossy meringue.
Sprinkle the cornflour, vinegar and ground nuts over the surface of the meringue and gently fold in. Tip into the lined tin and spread level.
Bake for 10 minutes then reduce the oven to 160℃ (140℃ fan)/400°F/gas mark 3 and bake for a further5 minutes until just firm to the touch and beginning to crack.
Meanwhile, place a clean tea towel on the work surface and place a sheet of parchment on top. Lightly sprinkle with a little caster sugar. Turn the cooked meringue out onto the parchment and allow to cool for 1 hour, before carefully peeling the lining parchment away.
Whip the cream until just beginning to hold its shape. Add the lemon curd and whisk until soft peaks form. Spread over the meringue.
Spread the raspberries evenly over the cream. Roll up the meringue starting at one of the short sides using the parchment and teatowel to help you. Carefully transfer to serving plate and serve with extra berries and a few chopped or shredded nuts if desired
Use a good quality lemon curd that is not too stiff. Nutrition information is approximate and is meant as a guideline only. IT does not include the extra nuts and raspberries, to serve.