1. Roll the meat in the flour and shake off the excess.
2. Preheat the oven to 375°F.
3. In a thick-bottomed pot, heat 4 tablespoons of oil; add the onions and the meat. Cook, turning the meat once, until the pieces are lightly browned.
4. Add the peeled and sliced carrots, the tomatoes with their juice, the bouquet garni, the white wine, the crumbled broth cubes, the orange zest, 2 cloves of garlic, a pinch of salt, and pepper to taste.
5. Cover the pot and simmer for 25 minutes over low heat. Bake for 1 hour.
6. Prepare the traditional gremolata: finely grate the lemon zest and mix with 2 chopped cloves of garlic and the chopped parsley. Reserve.
7. Remove the osso buco from the oven. Quickly incorporate the gremolata, cover the pot, and let the flavors develop for 5 minutes. Serve immediately with al dente tagliatelles or saffron risotto (to be very traditional).