Serves 4

This is a great way to flaunt the delicate flavour of the iceberg lettuce. I’ve added a little bit of curry powder to give the soup a lift but you could keep it simple and omit the ground spice. Chilled soups will need more salt and pepper to bring out their muted flavours, so always err towards slightly over-seasoning the soup.

For the soup
2 tbsp olive oil
1 large (or 2 medium) onions, peeled and
finely chopped
1⁄2 tsp mild curry powder
Leaves from a few sprigs of thyme
Sea salt and freshly ground black pepper
1 litre vegetable stock
1 large head of iceberg lettuce, trimmed and
finely shredded
150-200ml Greek yoghurt or crème fraîche
(optional)
Squeeze of lemon juice, to taste

For the prawn toasts
8-10 large king prawns, peeled and
deveined
Sea salt and freshly ground black pepper
1 medium free-range egg white
1 tbsp double cream
Pinch of freshly grated nutmeg
Squeeze of lemon juice
4 mini-baguettes, sliced diagonally
5-6 tbsp sesame seeds
Vegetable oil, for deep frying

1 First make the soup. Heat the oil in a large pot and add the onions. Stir in the curry powder, thyme, salt and pepper, then cover the pan with a tight-fitting lid and cook over a low heat for 7-8 minutes until the onions are soft and translucent.
2 Pour in the stock and bring to the boil. Lower the heat to a simmer and cook for a few minutes to allow the onions to infuse with the stock. 
3 Increase the heat and bring the stock back up to the boil. Tip in the shredded lettuce. Stir the lettuce through the hot stock and cook briefly for about 30 seconds until the lettuce has just wilted. (Initially, it may seem that there is not enough stock for the amount of lettuce, but don’t despair – the lettuce will wilt and further dilute the soup.)
4 Remove the soup from the heat and blend to a very smooth purée in two batches. Season generously with salt and pepper to taste. If you prefer the soup thick and creamy, stir in some Greek yoghurt or crème fraîche and blend well. Otherwise, season the soup with a squeeze of lemon juice to taste.
5 Cool the soup completely (in an ice bath to speed up the process), then transfer to a large bowl, cover with clingfilm and chill for several hours or overnight.
6 Prepare the prawn toasts. Place the prawns in a food processor and pulse to a coarse paste. Add a pinch of salt, black pepper and the egg white and pulse again. Add the cream, nutmeg and lemon juice and give it a final whiz. Transfer the prawn paste to a bowl, cover with cling film and chill for 15 minutes to let it firm up slightly.
7 Spread a generous layer of prawn paste on the baguette slices, then dip into the sesame seeds to coat.
8 Heat a pan with 2-3cm of vegetable oil until hot. Add the prawn toasts, paste-side down, and fry for a few minutes until golden brown. Flip over and fry the other side until golden and crisp. Drain on kitchen paper and lightly sprinkle with sea salt. Serve immediately with the bowls of chilled iceberg soup.

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