Onions peel, roughly dice. Peel garlic and chop finely. Peel and chop carrots and celery. Wash parsley, shake dry. Chop 1/2 bunch coarsely. Put the rest of the parsley aside. Heat 2 tablespoons of oil in a frying pan. Fry the carrots, celery, onions and half of the garlic until lightly browned. Stir in tomato paste and sauté briefly. Take the roaster off the heat and put it aside
Wash the meat, dab dry and cut the almost transparent silver skin more often, but do not cut into the meat. Wrap leg slices tightly with kitchen string. Season with salt and pepper. Turn in flour. Tap off excess flour. Heat 3 tablespoons of oil in a large frying pan. Fry the leg slices on both sides at medium heat for about 3 minutes until golden brown. Remove the meat and place it on the roasted vegetables in the roasting pan.
Deglaze the frying pan with wine. Bring to the boil and simmer until it has dissolved. Add tomatoes, beef stock, cloves, cardamom and cinnamon. Bring to the boil. Season to taste with salt and pepper. Pour tomato sauce over the meat. Put the lid on top. Braise in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for 2-3 hours until the meat is tender
In the meantime, for the Gremolata, roast the almonds in a pan without fat, turning them golden brown. Let it cool down on a flat plate. Wash the lemon, grate dry and finely grate the peel. Finely chop the remaining parsley. To ensure that the flavours combine well, chop the garlic, parsley and lemon peel together on a board. Mix with almonds, set aside
For the polenta, bring milk, fat, 1 teaspoon salt and 700 ml water to the boil in a saucepan. Stir in the corn semolina and let it simmer at low heat while stirring for about 4 minutes. Remove from the heat and let it swell for about 15 minutes covered. Grate cheese. Stir 1 tablespoon of oil and cheese into the polenta. Season to taste with salt. Serve the ossobuco with the tomato sauce. Sprinkle Gremolata on top. Add the polenta