Whisk together the egg yolks and the sugar to make a sabayon: beat the mixture until it is pale and fluffy and has tripled in volume.
Whisk the double cream to soft peaks.
Mix together the mascarpone and the pistachio paste and then gently fold into the sabayon. Fold in the whipped cream.
Wash the strawberries and remove the stalk. Cut them in half and place in a blender. Add the water and the sugar and then blitz to a smooth purée.
Serve the tiramisu in glasses. Start with a layer of pistachio cream and then add a layer of sponge fingers. Add a spoonful of strawberry purée and repeat the layering process until the glasses are full. Sprinkle with chopped pistachio and then chill for 1 hour before serving.
«This recipe also works well using raspberries instead of strawberries.»