Place carrots, celery, onion, and garlic in the bottom of a slow cooker.
Pound steaks to ¼ inch thickness (if using cube steaks, skip this step). Season with salt and pepper, then dredge in flour.
Brown steaks in a hot skillet with oil for about 2 minutes per side. Add wine to the pan to deglaze, then pour into the slow cooker.
Add beef broth, tomatoes with juice, tomato paste, Worcestershire sauce, and thyme to the slow cooker. Stir well.
Cover and cook on low for 6-8 hours or on high for 4-5 hours until steaks are tender.
(Optional) Thicken the sauce with cornstarch before serving.
Enjoy!
