Melt the butter in a heavy-based, non-stick pot. Add the celery, onion and the corn from six ears of sweetcorn and sweat it down (that is, cook it gently without the vegetables taking on any colour). Add two to three pinches of salt and three pinches of pepper.

When the onion, celery and corn has softened, add the stock cubes (or bouillon) and mix well to dissolve. Add the flour, turn the heat down low and mix well. Now add the water to your roux, and whisk out the lumps, until it is smooth. As the water heats, the mixture will thicken. At this point whisk in the cream to bring it to a smooth consistency. Turn the heat up and whisk every two minutes, until it comes to the boil. Blend the bisque using a food processor or a stick blender until it is smooth and then pass it through a sieve. Add the fresh tarragon, and blend again until it iscorporated. Set aside.

For the charred corn: Bring 500ml water to the boil. Add three pinches of salt then the remaining sweetcorn and cook for two minutes. Drain well and set on some kitchen paper to dry completely. Heat a cast iron pan until it is smoking. Add the sweetcorn and cook until charred/blackened.

To finish, taste and adjust the seasoning, if necessary, then pour the soup into bowls and finish with a generous sprinkling of charred corn.