Dust the veal shanks lightly with flour. Melt the butter in a large frying pan over medium to medium-high heat. Add the veal and cook until browned on the outside. Remove to a bowl and keep warm. Add two cloves of crushed garlic and onion to the frying pan; cook and stir until onion is tender. Return the veal to the pan and mix in the carrot and wine. Simmer for 10 minutes.
Pour in the tomatoes and beef stock and season with salt and pepper. Cover and simmer over low heat for 1 1/2 hours, basting the veal every 15 minutes or so. The meat should be tender, but not falling off the bone.
In a small bowl, mix together the parsley, 1 clove of garlic and lemon zest. Mix into the veal just before serving.
Veal shanks can be purchased in your local butchers. You may need to pre-order them.