Swiss roll tin 12 x 8 inch (30.5 x 20.5cm)
First, make the meringue:
Preheat the oven to 180C\350F\regulo 4.
Put the egg whites into the spotlessly clean bowl of a food mixer. Break up with the whisk and then add all the castor sugar in one go. Whisk at full speed until the meringue holds a stiff peak 5 minutes approx.
Meanwhile, line a swiss roll tin with non-stick baking paper. Spread the meringue gently over the tin with a palette knife and sprinkle over the chopped pistachio nuts. Bake in the preheated oven for 20 minutes. Allow to cool and sprinkle lightly with icing sugar.
Turn the meringue out onto a sheet of grease proof paper and peel off the baking paper. Fold the elderflower cordial into the whipped cream. Turn the meringue so a long side is facing you. Spread three quarters of the whipped cream over the meringue, leaving a 1 inch border on the long side furthest away from you. Arrange the strawberries on top, pressing them into the cream. Starting at the long side nearest you, and using the greaseproof paper, carefully roll up the meringue. Unwrap the roulade and transfer carefully onto a serving plate. Pipe some rosettes of the remaining cream onto the top, decorate with the strawberries segments, sweet cicely leaves and geranium flowers. Serve with fresh strawberry sauce.
To make the strawberry sauce, clean and hull the strawberries, add to a blender with sugar and blend. Strain, taste and add lemon juice if necessary.