Place the flour in a medium-sized bowl, then season with salt and pepper. Season beef on both sides with salt and pepper. Make small cuts in the outer membrane of the beef osso buco so that the meat doesn’t twist out of shape while it braises. Dust the beef in the flour, shaking off any excess, then set aside.
Heat half of the olive oil and butter in a large heavy-based stockpot (preferably cast iron) over medium-high heat. Cook the osso buco until nicely browned on both sides. Remove from stockpot and set aside.
Heat the remaining olive oil in the stockpot over medium heat. Add the onions, garlic, carrots and celery and cook until the onion is tender (about 5 minutes). Return osso buco to pan, add bay leaves and wine and simmer until reduced by about half (about 5 minutes). Add tomato and beef stock, and bring to the boil. Reduce the heat to low, cover and simmer for a further 1½ – 2 hours or until the osso buco is tender. Check the amount of liquid in the pot from time to time and add more water if required. Discard the bay leaves.
Meanwhile to make the Risotto alla Milanese, bring the vegetable stock (or chicken stock) and saffron just to the boil in a medium-sized saucepan over high heat. Remove from the heat and set aside. Heat the olive oil and half of the butter in a large, deep frying pan (or stockpot) over medium heat. Add the onion and cook for 3 minutes or until softened. Stir in the rice and after 2 minutes, pour in the wine. Cook, stirring, until all the liquid has been absorbed. Add a ladleful of the hot stock, stirring constantly. When the stock has been absorbed, stir in another ladleful. Continue to add ladlefuls of stock, stirring and allowing each ladleful to be absorbed before adding the next until the rice is ‘al dente’ (approximately 15 minutes). Remove the frying pan (or stockpot) from the heat. Stir in the remaining butter and Parmigiano Reggiano.
Note: Chicken stock adds a deep, rich flavour, while vegetable stock creates a lighter risotto. We prefer to use vegetable stock as it is served with hearty Osso buco however if you want a tasty, meatier flavour, use chicken stock.
Meanwhile to make gremolata, mix together the parsley, garlic, and lemon zest in a small bowl.
Stir half of the gremolata into the osso buco and braising liquid. Serve osso buco with braising liquid spooned over and Risotto alla Milanese on the side. Sprinkle the remaining gremolata on top and serve immediately – buon appetito.