Heat olive oil in a large skillet over medium-high heat. Add the thinly sliced beef in a single layer and cook for 3-4 minutes without moving to achieve a brown sear. The beef should be cooked through but still tender.

Remove the beef from the skillet and set aside. In the same skillet, add bell peppers, onions, and mushrooms. Sauté for 5-7 minutes until tender and slightly caramelized. Add minced garlic during the last minute and cook until fragrant.

While vegetables cook, melt butter in a separate skillet over medium heat. Add riced cauliflower and sauté for 5-7 minutes until tender and lightly golden. Season with salt and pepper.

Return the beef to the vegetable skillet, add Worcestershire sauce, and season with salt and pepper. Stir for about one minute to combine flavors. Arrange provolone cheese strips over the mixture, then cover the skillet for 1-2 minutes until cheese is melted.

Divide the cauliflower rice among four bowls and top with the beef and vegetable mixture. Garnish with fresh parsley and serve immediately.