Make this soup when fresh sweetcorn is at the height of its season. The bacon is added at the last minute to retain its crispness, the cheese allowed to melt on top of the soup.
Remove the husks from the corn, then hold each cob upright on a work surface and cut off the kernels with a knife. Put the corn kernels in a pan with the milk and bring to the boil. Reduce the heat and simmer for 10-15 minutes, until tender. Drain the corn and reserve the milk.
Melt the butter in a saucepan and gently sauté the onion and celery in it until soft. Add the flour, cook for 2-3 minutes over a low heat and then gradually stir in the milk and stock. Slowly bring to the boil, stirring all the time, until thickened. Reduce the heat and simmer for 15-20 minutes. Add the corn and half the cheese and cook very gently for 5 minutes, then pour into a blender and blitz to a purée. Reheat and season to taste.
Grill the bacon slices until crisp, then crumble them. Sprinkle the bacon over the soup with the remaining cheese just before serving.