For the marrow bone ragout
Chop the celery, carrot and onion into a little brunoise; sous vide the marrow bone, bay leaf, salt and evo oil. Cook for 10 hours at 71°C then chop the marrow bone for the ragout, add the vegetables, the tomato purée and the brown stock and cook for 20 minutes.
For the creamed rice
Make a classic risotto alla milanese by toasting the rice, then adding the vegetable stock, followed by the saffron, and cooking for 20 minutes. Then mix in the Grana Padano and butter. Blend the rice until it turns into a smooth, even cream. If necessary add some stock and set to one side for mixing with the spaghetti.
For the gremolada
Zest the lemon and chop the parsley, then put in a container and cover with evo oil.
Cook the spaghetti in plenty of salted water, drain and mix in the creamed rice, serve onto plates and add the marrow bone ragout on top and garnish with the gremolada.