Iced Lemon Courgettes

• 3 lemons
• 4–5 medium courgettes, sliced into batons about 2.5 cm (1 inch) long
• 1 medium onion, very finely sliced

Using a sharp serrated knife, remove all the peel and pith from the lemons. Cut them into segments, removing all the membrane (like grapefruit segments). Now put them into a saucepan with all the other ingredients, apart from the parsley, and bring up to simmering point. Cook gently for 15–20 minutes, stirring from time to time. Season to taste and chill before eating. Add some parsley just bef