Season shank with sea salt and pepper. Sear off the shank in a hot roasting pan with oil and butter in a preheated 450 degree F oven. Continually baste shank and cook until brown. Add mirepoix (carrots, celery and onions) and brown slowly. Add white wine and bouquet garni (garlic, bay leaves, thyme, parsley, and peppercorns) wrapped in the green leek. Continually baste while roasting. Cook for about 2 to 3 hours until shank is bronzed and fork tender, with no liquid left in pan. Remove shank and add water to pan and reduce to make a sauce. Strain and reseason with sea salt and pepper.;
CABBAGE: Heat a rondeau, add bacon fat, duck fat, onions, and shallots. When shallots are lightly caramelized, add cabbage. Season lightly with salt and pepper and cook until cabbage is lightly caramelized. Add caraway, white wine, and oxtail stock. Reduce down. Add butter, vinegar and check seasoning.
CIPPOLINI ONIONS: In a large saute pan, melt butter and sugar. Stir in cippolini onions, salt and thyme, then pour chicken stock over onion mixture to cover. Cook until onions are glazed and lightly caramelized. Set aside.
TOMATO MARMALADE: Over medium heat in stainless steel saute pan, combine all ingredients completely. Cook until dry or jam-like consistency. Check seasoning.
PLATING: Place cabbage on plate, top with shank. Ladle onions and marmalade over top, then sprinkle with truffle oil, thyme leaves, fleur de sel or sea salt, cracked pepper.