1. Drain any liquid from the package of corned beef and put the meat in a large pot with the bay leaf, garlic, peppercorns, mustard seeds, cloves, allspice, and onions. Add enough water to cover by about 2 inches. Bring to a boil and skim off the foam that rises to the surface.
2. Lower the heat so that it bubbles gently. Cover and cook, turning the meat every 30 minutes or so, for about 2 hours. Pierce the thickest part with a thin-bladed knife; the meat is ready when the knife can be inserted to the middle without much resistance. If the meat is not done, continue cooking it, checking every 15 minutes. Heat the oven to 300°F.
3. Transfer the meat to a rimmed baking sheet, fat side up, and put it in the oven while the vegetables cook in the seasoned broth. Or wrap it in foil, put the broth into an airtight container, and refrigerate both for up to 2 days. Reheat the foil-wrapped meat at 300°F for about 30 minutes; unwrap and heat for about 15 minutes more. Skim any fat off the broth and pour the broth back into the pot (you can strain it if you’d like and discard the solids).
4. Add the potatoes to the broth in the pot along with about 2 cups water, and bring to a boil. Cook for about 5 minutes, then add the carrots and cabbage. Adjust the heat so the broth bubbles steadily, cover, and cook until the vegetables are tender, 10 to 15 minutes. Slice the corned beef thin against the grain, and serve in shallow bowls with the vegetables and broth.

— Recipe from How to Cook Everything: Completely Revised Twentieth Anniversary Edition