Mix the rosemary, bay leaf, coriander and oil in a large bowl. Add the beef cubes, and toss well, Cover with plastic wrap, and refrigerate for an hour.
Remove the beef cubes and sprinkle with salt and pepper to taste, dredge in flour. Strain the marinade oil and set the herbs aside for later use. Put the strained oil in a dutch oven. Heat oil over high heat and cook the beef in batches until browned on all sides. Set the browned meat aside. Add the onion and celery to the pan, adding additional oil if needed to brown the onions for 3-4 min on high heat. Lower the heat to medium, add the garlic and cook for another 1 min. Return the meat to the pan, adding the wine and simmer until the wine is reduced by half, about 4 min.
Stir to remove the bits of cooked meat from the bottom of the pan, add 1 quart of the stock, and the reserved herbs. Bring to a boil, cover the pot and remove from the heat. Place pot in the oven and bake in a 350” oven for 45 minutes. You can pour the mixture into a baking dish if desired.
Bring the remaining 3 cups of stock to boil in a saucepan over medium heat. Stir in the couscous and simmer for 10 min, or until the liquid is absorbed.
Remove the beef from the oven, remove and discard the bay leaf and stir in the cooked couscous until it is well coated with the sauce. Cover the pot and allow to stand for 5 min before servings.
Ladle the stew into bowls and top with the parsley.