Crockpot Swiss Steaks

Name: Crockpot Swiss Steaks
Prep time: 20 min
Cook time: 6 h 15 min
Total time: 6 h 35 min
Ingredients: 1 ½ pounds round steak (or cube steaks or minute steaks); 2 carrots (sliced into 1-inch pieces); 1 rib celery (sliced into 1-inch pieces); ½ yellow onion (sliced ½-inch); 2 cloves garlic (sliced); ¼ cup all-purpose flour; 1 tablespoon olive oil; ½ cup white wine; 1 cup beef broth; 1 (14.5 ounce each) can diced tomatoes (with juices); 2 tablespoons tomato paste; 1 tablespoon Worcestershire sauce; ½ teaspoon dried thyme leaves; salt and black pepper (to taste); cornstarch (optional, for thickening)