Wash, peel and grate the carrot in a medium coarse manner. Wash the fresh celery, pluck the flawless leaves, have 2 tablespoons ready and freeze the rest. Cut the flawless stems crosswise into pieces approx. 3 mm wide. Measure out the required amount and freeze the rest. Measure frozen goods and allow to thaw.
Cap the onion and garlic at both ends, cut in half lengthways, peel and cut into small pieces. Heat 2 tablespoons of the olive oil in the pan over moderate heat and add the prepared vegetables, fry until lightly browned. Remove from heat and put in a saucepan. Remove the stems from the tomatoes, peel them, quarter them, core them and keep them ready.
Salt and pepper the veal shank slices on both sides. Roll in the flour and fry light brown on both sides with 2 tablespoons of olive oil. Place the slices on the vegetables in the saucepan. Dissolve the beef broth in the boiling water and mix in the tomato paste with the herb mix. Pour half of it over the slices.
Put the lid into the oven preheated to 180 degrees and fry for at least 2.5 hours. Pour the remaining sauce over every 30 minutes. After 2 hours add the tomato pieces and pour the rest of the sauce over them.
Serve the finished osso buco alla milanese as a secondi piatti in the casserole and enjoy.