Place a small metal tray into the freezer to chill. Put the lemon verbena, lemon zest, and sugar into the boiling water and allow to infuse for 10 minutes. Add your ice cubes to bring the temperature down and then sieve the liquid into the cold metal tray (keep the lemon zest and verbena for later) and place in the freezer for about 2 hours. Mash with a fork, scratching up the ice, then freeze for a further 2 hours.
To prepare the apple compote, put 2 tablespoons of sugar into a small pan and heat on a medium heat until it is syrupy and light caramel color. Finely chop the reserved lemon zest and lemon verbena and add to the caramel with the apple and lemon juice. Mix and cook for a couple of minutes.
To serve, spoon a little compote into 4 small shot glasses, then a spoonful of creme fraiche, and finally top with the granita and a small sprig of lemon verbena.
(c) Jamie Oliver 2003