In a large skillet over medium-high heat, brown the ground beef until fully cooked, approximately 6-8 minutes, breaking it into small crumbles. Drain excess fat if necessary.
Add the sliced onions, bell peppers, and mushrooms to the skillet. Sauté for 5 to 7 minutes until the vegetables are tender and slightly caramelized.
Incorporate the minced garlic, Worcestershire sauce, salt, and black pepper. Cook for an additional 2 minutes until fragrant.
Reduce the heat to low. Layer the provolone cheese slices evenly over the beef and vegetable mixture. Cover the skillet with a lid for 60 seconds or until the cheese is completely melted.
Divide the cooked cauliflower rice or white rice into four bowls. Portion the cheesesteak mixture over the base and serve immediately.