Bring the water and sugar to the boil, let it boil for a few minutes, then let it cool completely.
Stir in the lemon juice and the raspberry syrup.
Place in a shallow dish in the freezer and rake thoroughly with a fork every 30-40 minutes, until it becomes a lovely, crumbly, icy sorbet (this takes about 3-3.5 hours); can also be made in an ice cream maker.
To serve, spoon into glasses, filling them halfway.
If available, top up with sparkling wine or dry white wine mixed with soda water, and finish with a spoonful of whipped cream.
Based on: Malatinszky Fanny szakácskönyve (a classic Hungarian cookbook), modernised. Calories and protein are estimated.