How to Make It
In a pot, heat the duck fat. Add the ham hock and cook over moderate heat, turning, until browned, 5 minutes. Add the chopped onion and carrots, sliced turnip, shredded cabbage, mushrooms and garlic and cook, stirring, until lightly golden, 5 minutes. Add the wine and cook until absorbed. Stir in the thyme, bay leaves, peppercorns and stock; simmer until reduced to 4 cups, 1 hour. Strain into a bowl and wipe out the pot. Return the broth to the pot and bring to a low simmer. Add the baby turnips and carrots and pearl onions, cover and simmer until almost tender, 15 minutes. Add the cabbage pieces and Romanesco, cover and cook until tender, 10 minutes. Stir in the beans and vinegar and season with salt; keep warm.
In a nonstick skillet, heat the duck fat, if using. Add the bacon and cook over moderate heat, until browned; transfer to paper towels. Strain the fat into a bowl. Wipe out the skillet.
Heat half of the reserved bacon fat in the skillet. Season the scallops with salt and cook over moderately high heat until golden on the bottom, 3 minutes. Turn the scallops and add 1 tablespoon of the butter. Cook, basting the scallops, until just opaque; transfer to a plate. Repeat with the remaining fat, scallops and butter. Stir the parsley into the stew, ladle into bowls and top with the scallops and bacon.
Banyuls vinegar is an aged sweet wine vinegar from the south of France. Cave de L'Abbé Rous makes a very good version; it's available from amazon.com.