Step 1Heat the oven to 350 degrees.
Step 2Heat the oil in a large skillet over medium heat. Add the garlic and onions and cook until soft, about 5 minutes.
Step 3Transfer the garlic mixture to a large, heavy roasting pot and place the meat on top, fat side up. Add the carrots, parsley, the tomatoes and their juice, the wine and garlic cloves. Season to taste with salt and pepper. Bring to a boil, cover and bake until the meat is tender, 3 to 4 hours. Add the prunes the last 30 minutes of baking.
Step 4Transfer the beef to a wooden board and slice across the grain. Return to the pot, squeeze the garlic from the cloves into the sauce, and keep warm until serving.