Heat the oil in a large saucepan over a moderate heat.

Add the onions and bacon, if using, and saute until softened. Add the potatoes, garlic, tarragon or thyme, and flour. Stir for several minutes until fragrant. Add the stock to the pan and bring to a gentle simmer. Cook for 10 minutes until the potatoes are just tender.

Remove the husk from the corn, and cut the kernels from the cob – to do this I set the base of the corn in a bowl and use a small sharp knife to cut down the length of the cob. Add to the soup and cook for a further five minutes.

The next step is optional but gives the chowder a more creamy consistency. Scoop half of the soup into a bowl and use a stick blender to blend until smooth. Pour back into the pot and reheat.

Add the cream and reheat gently. Check and adjust seasoning to taste. Ladle into soup bowls and scatter with thyme leaves. Serve with freshly baked sourdough bread.