Melt 50g (2oz) of the butter in the casserole. Add the sliced leeks, stir well to coat with butter and season lightly. Place on the lid and cook over a low heat for 5 minutes until just tender. Remove the leeks with a slotted spoon onto a plate and set aside. Drain the sweet corn into a bowl, reserving the liquid.

Add the sunflower oil to the casserole with the bacon and fry over a high heat until beginning to brown. Remove the bacon and leave to one side. Lower the temperature to a medium heat and add the remaining butter, onions and red peppers, cover and cook gently for 10 minutes until they have softened.

Stir in the flour and cook for 1 minute. Gradually stir in the chicken stock, milk and reserved liquid from the sweet corn and bring to the boil. Add the potatoes, bay leaves and 1 teaspoon of salt, cover and leave to simmer gently for 10-15 minutes or until the potatoes are tender and just beginning to fall apart.

Remove and discard the bay leaves, then press some of the potatoes up against the sides of the pan to break them up slightly. Stir in the sweet corn and cream and cook for 2-3 minutes until almost back to the boil. Stir in the leeks, bacon and half the chopped parsley and season to taste with cayenne pepper, salt and white pepper. Serve in warmed bowls, sprinkled with the rest of the chopped parsley.

Cook's Notes

To clean leeks, slit them open lengthways, separate the leaves slightly and wash away any mud or grit. Shake away the excess water before slicing and cooking.

Look out for packets of cooked ham hock in the chilled cabinet at the supermarket. Use in place of the bacon lardons, stirring them in with the sweet corn towards the end of cooking.

If you can, use a homemade stock for this soup. Stock leftover from cooking gammon or a collar of bacon would be even better.