Rinse the veal shanks with cold water and pat dry. Peel the carrots and cut them into strips. Clean the celery and the leek, wash them, then cut them into strips. Peel the garlic and onion and dice them. Skin the tomatoes, remove the stems and pits, then dice them. Heat the oil in a skillet. Sear both sides of the meat and season with salt and pepper. Add onions, carrots, celery, and leek to the skillet and briefly braise them. Douse with wine. Heat the oven to 180°C (356ºF).
Pour in the stock and add the tomatoes. Place the skillet on the bottom rung of the preheated oven and braise the shanks for about ninety minutes. Wash the parsley, pull the leaves, and mince them. Shortly before the end of the cooking time, add parsley, garlic, and lemon zest to the skillet. Season with salt and pepper, and puree the vegetable mixture into a thick sauce.
Peel the onions for the risotto and dice them. Add butter to a saucepan and lightly cook the chopped onion. Add the rice and stir until translucent. Add the wine and stir in the saffron. Bring the mixture to a boil and allow the rice to rehydrate. Slowly add, after the liquid has reduced, the meat stock to the saucepan. Allow the risotto to become creamy for about 25 minutes. Stir créme fraîche and Parmesan cheese into the rice and season with salt and pepper. Plate the risotto and place a veal shank on top.
Serve with vegetable sauce.