Celeriac ‘Cannelloni’

• 1 large celeriac (about 700 g/1 lb 9 oz)

Bring a saucepan of salted water to the boil. Using a knife, trim the top and base of the celeriac and peel the sides. Using a mandolin, slice the celeriac lengthways into 1 mm (1/32 inch) thick slices. Bl