Slow Cooker Guinness Beef Stew

Name: Slow Cooker Guinness Beef Stew
Ingredients: 2 tablespoons butter; 2 pounds (900 g) well marbled chuck beef roast, cut into 2-inch pieces; Kosher salt; 2 cups chopped onion (about 1 large onion); 2 stalks celery , chopped; 2 tablespoons tomato paste; 1 pint ( 16 ounces , 475 ml) Guinness extra stout (make sure you use extra stout and not draught); 3 cups ( 700 ml) beef broth; 2 large carrots , peeled and cut into chunks; 3 to 4 parsnips , peeled and cut into chunks; 1/2 pound (280g) celery root , potatoes, or very young turnips, peeled and cut into chunks; 2 teaspoons dried thyme; 4 tablespoons chopped fresh parsley , optional