1. Sprinkle the meat liberally with the salt, pepper, and paprika. Scatter hald of the onions in a large pot or roasting pan. Add the brisket, the remaining onion, the bay leaf, and enough boiling water to cover. (Adding boiling water seals the brisket, resulting in a more flavorful meat; cold water produces a more flavorful broth.)
2. Bring to a boil and skim the foam. Cover, reduce the heat to low, and simmer for 1 1/2 hours.
3. Add the carrots, celery, and parsnip. Cover and simmer until the meat is fork-tender (there si only a slight pull on a fork when it is removed from the meat), about an additional 1 hour for brisket; 30 minutes for short ribs. (At this point, the meat can be refrigerated for up to 3 days; skim the fat from the surface, slice the meat, and reheat in the cooking liquid.)
4. Let the brisket stand in the cooking liquid for 15 minutes. Remove the meat and slice diagonally against the grain (the muscle lines). Serve the meat moistened with the broth (serve the leftover broth as soup) and accompanied with the vegetables and noodles or potatoes. Serve with grated horseradish or prepared mustard.Variations:
Tomato Brisket: Substitute 2 cups peeled, seeded, and chopped tomatoes and 2 cups dry red wine for water.