Cut the beef into 1 1/2-inch chunks. Preheat a large frying pan over medium-high heat and add a few tablespoons of oil. Once the pan is hot, add the cubed beef, season generously with salt and fry for 7 to 10 minutes, until well browned all over. Transfer the beef into a large soup pot. Deglaze the frying pan with 1/2 cup water and add the liquids to the soup pot.
Into the same frying pan, add 1 tablespoon cooking oil and the carrots, celery and onion. Saute the mixture over medium heat until the onions are translucent, about 4 to 5 minutes. Once the onion is tender, add the garlic and cook for 1 more minute. Transfer the mirepoix mixture into the soup pot. Into the frying pan, add the butter and allow it to melt before adding the mushrooms. Saute the mushrooms for 4 to 5 minutes, until well browned all over. Season the mushrooms with salt and then add the flour. Toss the mushrooms in the flour so they're evenly coated and cook for 1 minute; transfer the mushrooms into the pot.
To the soup pot, add the red wine, tomato sauce, Worcestershire, beef broth, spices and herbs. Season generously with black pepper and abou 1 1/2 tsp salt. Cover the pot with a lid and bring to a boil over high heat. Once boiling, reduce the heat to low and continue simmering the soup for 1 to 1 1/2 hours, or until the beef is tender.
Add the potatoes and frozen peas; if using fresh peas, add them 10 minutes later. Cook the potatoes for 20 minutes, or until fork tender. Garnish the stew with chopped parsley and enjoy.
Optional: for a richer stew, add the potatoes and continue cooking for an additional hour, bringing the total cooking to 2 or 2 1/2 hours.