Dredge the veal shank pieces well in flour. In a large skillet with high sides, heat the olive oil and butter over moderately high heat until the butter stops foaming. If you do not have a skillet large enough to accommodate all of the meat in a single layer, use two smaller pans.

Add the veal shanks to the skillet and arrange in a single layer. Cook over moderately high heat until browned on one side. Add a generous amount of salt and pepper. Turn meat and brown the other side, and add salt and pepper. Add enough white wine to nearly, but not quite, cover the meat. Reduce heat to a barely bubbling simmer.

Cover with a well-fitting lid. Cook at a simmer for 2 1/2 hours. Peel a thin layer of rind from the lemon. (I find that a vegetable peeler gives me a nice thin layer of rind.) Cut rind into fine strips. Remove veal shanks to a warm plate. The meat will be falling-off-the-bone tender, so a wide spatula is advised for this step to keep each shank intact. Keep meat warm through the next several steps. Add lemon peel and chopped parsley to the sauce and place over high heat.

Boil vigorously for several minutes to reduce sauce slightly. Stir to loosen any brown bits from the pan and then frequently to prevent burning. Remove from heat and return shanks to skillet. Spoon sauce over shanks and replace skillet lid. Let sit for 3-5 minutes to reheat shanks. Serve with sauce over shanks.