This is a favourite with Fiona Clark, see her thoughts here.

Ingredients

2 tsp olive oil
2 leek, finely sliced
550g potato, cut into small cubes
1litre fish stock
1 lemon, zest only
300ml whole milk
330g can sweetcorn, rinsed and drained
250g skinless, boneless salmon, cut into chunks
250g skinless, boneless white fish, cut into chunks
handful chives, snipped with scissors
2 tbsp double cream (optional)

Method

1. Heat the oil in a large saucepan, tip in the leeks and fry gently for 5 mins until softened, but not coloured. Add the potatoes and cook for a further min. Pour in stock and lemon zest, cover and simmer for 12-15 mins or until the potatoes are tender. With a slotted spoon, remove half the potatoes and leeks from the stock and set aside.
2. Transfer the remaining potatoes, leeks, stock and milk into a blender or food processor and whizz until smooth. Pour back into the pan, add the sweetcorn, fish and reserved vegetables. Cover and gently heat for 3-4 mins until the fish is just cooked through – don’t boil. Stir in chives and cream, if using, then season to taste.

Source: BBC GOOD FOOD