Heat the vegetable oil in a skillet over medium-high heat. Season the cube steaks with salt, pepper, onion powder, and paprika.
Once the oil is hot, sear the cube steaks in the skillet for 2-3 minutes on each side until browned. This step is optional but adds extra flavor.
Place the sliced onions and minced garlic in the bottom of the slow cooker. Lay the seared cube steaks on top of the onions.
In a bowl, mix together the beef broth, cream of mushroom soup, and Worcestershire sauce. Pour this mixture over the cube steaks in the slow cooker.
Cover and cook on low for 6 hours or until the steaks are tender.
If you prefer a thicker gravy, combine cornstarch and water in a small bowl to create a slurry. Stir it into the gravy about 30 minutes before serving, and let it cook on high for a thicker consistency.
Serve the cube steak and gravy over mashed potatoes, rice, or egg noodles for a hearty meal.