Remove the steaks from the refrigerator 30–45 minutes before cooking so they come to room temperature. This helps them cook evenly. Meanwhile, prepare the chimichurri sauce by combining parsley, garlic, and oregano in a bowl. Add olive oil, red wine vinegar, red pepper flakes, salt, and black pepper. Stir well and let it sit for at least 10 minutes to allow the flavors to blend.

Pat the steaks dry with paper towels to remove any surface moisture. Generously season both sides with salt and freshly ground black pepper, pressing the seasoning into the meat to enhance flavor and help create a crust.

Heat a cast-iron skillet or grill pan over high heat for 3–5 minutes until very hot. Add olive oil and swirl to coat the pan. Place the steaks in the pan and sear without moving for 3–4 minutes until a deep golden crust forms. Flip and cook another 3–4 minutes for medium-rare, adjusting time based on your preferred doneness.

Transfer the steaks to a cutting board and let them rest for 5–10 minutes. Slice against the grain into thin strips, then arrange on a plate and drizzle generously with chimichurri sauce. Serve immediately with extra sauce on the side.