We don't cook enough with celery and it's a tasty addition to all sorts of dishes. I've used it here with mature pecorino, but you could add pieces of bacon or ham hock – or just leave it vegetarian.
1 head of celery
1ltr hot vegetable stock, or a good-quality stock cube dissolved in that amount of hot water
2tbsp olive oil
1 medium onion, peeled, halved and finely chopped
200g carnaroli rice
2tbsp double cream
60-80g freshly grated pecorino Romano
For the stock
The trimmings from the celery
1 onion, peeled and roughly chopped
1.5ltrs vegetable stock
Trim the root away from the celery and discard. Remove the outer, large, stringy stems from the celery and roughly chop them. Reserve any leafy tops to chop into the risotto at the end. Put the chopped outer stems in a saucepan with the onion and stock, bring to the boil and simmer gently for 1 hour, then strain through a fine-meshed sieve. Check the strength; keep simmering if it's not strong enough.
Meanwhile, cut the rest of the celery into rough 1cm dice and simmer in a little of the stock until just cooked; strain the stock back into the main batch and put the celery to one side with any chopped tops.
Heat the olive oil in a heavy-based saucepan and gently cook the onion for a few minutes until soft. Add the rice, stirring it well with a wooden spoon over a low heat for a minute. Gradually add the hot stock a little at a time, stirring constantly and ensuring that each addition has been fully absorbed by the rice before adding the next.
When the rice is almost cooked, add the cooked celery and any leaves, season and continue adding the stock and cooking in the same way until the rice is soft, but still a little al dente and plump. The risotto should be quite moist at this stage, not dry and not too wet. Add the butter, cream and half of the pecorino. Correct the seasoning and serve with the rest of the pecorino.