Heat a large saute pan over medium-high heat. Add the olive oil and the beef.Season with the salt, the spice rub, and black pepper. Sear the beef for about 2 or 3 minutes per side or until the crust begins to caramelize.(Note: the beef should NOT be cooked all the way through.)
To the crock of a slow cooker, combine the butter, flour, beef stock, tomato paste, thyme, oregano, basil, allspice, and the browned meat.
Cover and set the temperature to high. Cook for 1 hour, then add the potatoes and cook for five hours.
Add the carrots, onion, mushrooms, and celery and continue to cook for another 2 hours.
Once done, stir in the parsley and serve over rice.