Crockpot Swiss Steaks

Bahan-bahan (4 porsi)

• 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)