1 Set the refrigerator to its coldest setting.
2 Place the lemons on a dinner plate and microwave on full power for 1 minute. (This will improve the juice yield.)
3 Grate the rind from 2 lemons, very finely, avoiding any pith.
4 Squeeze the juice from the fruit and strain into a 2.25 litre/4 pint (10 cup) mixing bowl.
5 Put the sugar and water into a very large bowl (see Note). Stir, then microwave on full power for 4 minutes. Stir once during cooking. Stir again to ensure that sugar has dissolved.
6 Add the grated lemon rind. Cover with plastic wrap and pierce. Microwave on full power until boiling point is reached, about 4 minutes.
7 Stir and return to microwave oven, cook on full power for
8 minutes.
8 Strain the boiled syrup very carefully into the lemon juice.
9 Pour the mixture into ice trays and cool.
10 When cold freeze until mushy. This will take about I hour.
10 Turn into a large cold bowl, and beat until the mixture is almost white.
11 Quickly beat the egg white to soft peak stage. Fold into the sorbet, using a metal spoon.
12 Freeze until firm (3-4 hours).