Season the shanks with salt and pepper and place a heavy casserole or Dutch oven on high heat. When hot add 50 ml of the oil, wait for a minute to heat up and add the shanks. Sear on both sides until nicely browned. Remove from fire and keep aside.
Remove any fat residues and add the remaining oil. Add the onions, carrots and celery and sauté until nicely colored while frequently stirring and tossing. Add the garlic and sauté until fragrant, about 40 seconds. Add the tomato paste and stir for a couple of minutes. Then Deglaze with the wine and let reduce by half and the alcohol to evaporate.
Return the shanks to the casserole and pour the chicken broth. Season with a bit of salt and pepper, add half of the thyme and rosemary, bring to a boil and simmer with the lid covered for about 2 hours until the meat is tender. If needed add some more water.
When cooked, remove the shanks from the casserole, increase the heat and reduce aiming for a nice thick sauce. Remove any fat residues while cooking.
To serve, plate the risotto in a flat dish and add on top the remaining parmesan cheese, then place on top the shanks and sprinkle with and the parsley the rest of the thyme and the lemon zest. Finish the dish with a drizzle of olive oil.