The soup can be made up to 4 weeks
ahead and frozen, or a few days in advance
and stored in the fridge.
Heat the oil in a large pan over a medium heat and add the celeriac, shallots and garlic. Gently fry for a few mins, until they soften without colouring. Add the white wine, bring everything to the boil and reduce the liquid by half. Add the chicken stock and nutmeg, bring to the boil again, then reduce the heat and simmer for 10-15 mins or until celeriac is tender. Remove from the heat and cool for 5 mins.
Transfer the soup to a food processor and blend until smooth. Pour the soup back into the pan, add the cream and generously season with salt and freshly ground pepper. Reheat gently while you finish everything else.
In a large frying pan, fry the black pudding until crisp. Set aside on kitchen paper to soak up any fat. Wipe out the pan.
Season the scallops. Heat the frying pan again until hot and add the butter. When it is foaming, add the scallops and sear for 1 min on each side, or until just cooked through, then place on a warm plate. To serve, pour the soup into 8 bowls, top each with 3 scallops and sprinkle with black pudding.