Prepare the Beef: Pat the steaks dry with paper towels. Season both sides with salt and black pepper.
Sear the Meat: Heat olive oil in a cast-iron skillet over medium-high heat. Once hot, sear the steaks for 3–4 minutes per side until a golden crust forms. Remove and set aside.
Sauté Aromatics: In the same skillet, add more olive oil if needed. Sauté minced garlic and onions until fragrant. Add bell peppers and mushrooms (if using) and cook until softened.
Make the Tomato Sauce: Pour in crushed tomatoes, oregano, red pepper flakes and basil. Stir well and bring to a gentle simmer. Season with salt and pepper.
Simmer the Steak: Return the seared steaks to the pan, spooning sauce over the top. Reduce heat to low, cover, and simmer for 45–60 minutes until the meat is tender.
Adjust Seasoning & Serve: Taste and adjust seasoning. Serve hot, topped with fresh basil or parsley.
Pairing Suggestion: Serve with pasta, polenta, or crusty Italian bread to soak up the sauce.