Osso Buco alla Milanese (Italian Miscellaneous)

Heat the oven to 300 degrees.
Dredge the legs: Pour the flour into a shallow dish (a pie plate works well). Season the beef thighs on all sides with salt and pepper. One at a time, roll the legs in the flour layer, shaking and patting to remove any flour excuse. Discard remaining flour.
Brown the legs: Place the oil and 1 tablespoon butter in a wide saucepan or heavy (6- to 7-quart) braising pot and heat over medium-high heat. When the butter has melted and the oil shimmers, lower the legs into the pot, flat side down; If the legs do not fit without touching each other, do this in batches. Brown the legs, turning once with tongs, until both flat sides are well caramelized, about 5 minutes per side. If the butter and oil mixture begins to burn, lower the heat slightly. Transfer the legs to a large plate or tray and set aside.
The aromatics: drain and discard the fat from the pot. Wipe off the burnt bits with a damp paper towel, being careful not to remove the delicious caramelized bits. Add the remaining 2 tablespoons of butter to the pot and melt over medium heat. When the butter has stopped foaming, add the onion, carrot, celery and fennel. Season with salt and pepper, stir, and cook the vegetables until they begin to soften but not brown, about 6 minutes. Add the garlic, orange zest, marjoram and bay leaf and cook for another minute or two.
The braising liquid: Add the wine, increase the heat to high and bring to a boil. Boil, stirring occasionally, to reduce wine by about half, 5 minutes. Add the broth and tomatoes, with their juices, and boil again to reduce the liquid to about 1 cup total, about 10 minutes.
The Stew: Place the legs in the pot so they are exposed bone side up, and pour over the juices that accumulated while they were resting. Cover with parchment paper, pressing down so the parchment almost touches the beef and the edges hang over the sides of the pot about an inch. Cover tightly with the lid and slide into the bottom of the oven to simmer. Check the pot after the first 15 minutes, and if the liquid simmers too aggressively, lower the oven heat by 10 to 15 degrees. Continue braising, turning the legs and pouring some pan juices over the top after the first 40 minutes, until the meat is completely tender and falling away from the bone, about 2 hours.
The gremolata: While the legs are cooking, mix the garlic, parsley, and lemon zest in a small bowl. Cover with plastic wrap and set aside in a cool place (or in the refrigerator, if your kitchen is very hot).
The Finish: When the veal is tender and falling off the bone, remove the lid and sprinkle over half the gremolata. Return the beef to the oven, uncovered, for another 15 minutes to caramelize it slightly.
Using a slotted spatula or spoon, carefully lift the legs from the braising liquid, doing your best to keep them intact. The legs will be very tender and threaten to fall apart, and the marrow will wobble around inside the bones, so this can be a little tricky. But if they break, don't worry, the taste won't be affected at all. Place the legs on a serving platter or other large plate, without stacking them, and cover with aluminum foil to keep warm.
Finish the sauce: Place the braising pot on top of the heat and evaluate the sauce: if there is a visible layer of fat floating on the surface, use a large spoon to skim it off and discard it. Taste the sauce to concentrate the flavor. If it tastes a little weak or flat, bring it to a boil over high heat and boil to reduce the volume and intensify the flavor for 5 to 10 minutes. Taste again for salt and pepper. If the sauce wants more flavor, add a teaspoon.