Celeriac and apple soup with girolle mushrooms and cheesy toasts

Method

1. Heat some olive oil or butter in a large heavy-based pan. Fry the onion until soft but not coloured. Add the celeriac, apple, thyme, nutmeg and bay. Pour in the veg stock and 500ml water, then bring to the boil. Simmer for 15 minutes, covered, or until the celeriac is tender. Put the soup into a food processor and whizz until smooth (or use a stick blender).Strain through a sieve, working it through with the back of a wooden spoon if necessary, then add the mustard, taste and season.
2. Turn the grill to high. Heat more olive oil or butter in a wide frying pan over a high heat, then add the girolle mushrooms. Fry until the moisture has evaporated and the mushrooms are golden. Throw in the chestnuts for 30 seconds, then tip on to a plate lined with kitchen paper.
3. Grate or slice the smoked cheese and scatter it over the bread. Grill for 5-7 minutes until the cheese is golden and bubbling. Ladle the hot soup into bowls, then top each with a scattering of the fried mushrooms and chestnuts. Scatter with thyme leaves, drizzle with cream, then serve with the toasts on the side.