Crockpot Beef Stew

Name: Crockpot Beef Stew
Ingredients: 1 pound beef chuck roast, cut into large chunks; Kosher salt and freshly ground black pepper; All-purpose flour, for coating beef; Olive oil, for searing beef; 3 to 4 carrots, cut into 2-inch pieces; 1 stick celery, cut into chunks; 12 or so pearl onions, peeled; 4 garlic cloves, minced; 1 cup halved cremini mushrooms; 1 teaspoon Worcestershire sauce, plus more to taste; 2 cups beef broth; Fresh flat-leaf parsley, roughly chopped, for garnish; Cooked white rice, for serving; 2 to 3 potatoes, cut into chunks