Coat the meat. Pat the beef dry and toss it with the flour until every cube is dusted, shaking off any extra.
Sear. In a large stockpot, heat the oil over medium heat and brown the beef in 2 batches for 4 to 5 minutes each until deeply colored, then set aside.
Sweat the vegetables. Cook the carrots, onion, and celery in the pot for 5 minutes, scraping the bottom, then add the garlic for 30 seconds.
Simmer. Return the beef, add the broth, water, seasonings, and bay leaves, bring to a boil, then reduce to low, partly cover, and cook 1 1/2 to 2 hours until fork tender.
Cook the noodles. Raise to a gentle boil and cook the noodles 8 to 10 minutes until tender.
Thicken. Whisk the half and half with the cornstarch, stir in, and simmer 3 minutes. Discard the bay leaves and top with parsley.