Place the raspberries in a food processor or blender and puree. Pass through a serve into a mixing bowl and set aside.
Put the sugar and water in a saucepan and stir over a gentle heat and boil rapidly for 5 minutes until the mixture becomes syrupy and sticky. Set aside to cool.
Add the syrup to the fruit puree together with the lemon juice and mix well.
Place the mixture in a rigid container, cover and place in the freezer until beginning to freeze around the edges.
Whisk the egg white until quite stiff and fold into the partly frozen mixture. Return to the freezer until solid.
