Pat the beef dry with paper towels. Trim away any silver skin and large pockets of fat, leaving a thin fat cap for flavor. If the cut is thicker than 2.5–3 cm (1 inch), butterfly it by slicing horizontally almost through and opening it like a book so it cooks more evenly.

Prepare marinade

In a bowl combine olive oil, soy sauce, Worcestershire sauce, minced garlic, chopped rosemary, thyme leaves, coarse salt, black pepper, brown sugar and red wine (if using). Whisk until the sugar has dissolved and the mixture is homogenous.

Marinate

Place the beef in a resealable bag or shallow dish. Pour the marinade over the beef, ensuring it is well coated. Massage the marinade into the meat. Refrigerate for at least 1 hour and up to 6 hours. Bring to room temperature for 30 minutes before cooking.

Cooking & Finishing

Preheat & Season

Preheat a heavy skillet (cast iron preferred) over medium-high heat for 5 minutes until very hot. Remove the beef from the marinade and let excess drip off; discard the used marinade. Pat the exterior lightly with paper towel. Season the beef evenly with sea salt and freshly ground black pepper.

Sear the beef

Add a tablespoon of neutral oil to the hot pan and swirl. Place the beef in the skillet and sear without moving for 2.5–3 minutes until a deep brown crust forms. Flip and sear the other side for 2–3 minutes. For thicker cuts, sear the edges for 30–60 seconds each to render fat and develop color.

Finish in oven (if needed)

If your cut is more than 2 cm thick and you want a precise internal temperature, preheat oven to 180°C (350°F) and transfer the skillet to the oven after searing. Roast 5–10 minutes depending on desired doneness: about 50–52°C for rare, 55–57°C for medium-rare, 60–63°C for medium. Use an instant-read thermometer inserted into the thickest part to check temperature.

Butter baste & rest

Return skillet to stovetop if removed. Reduce heat to medium-low, add unsalted butter and crushed garlic to the pan. Once butter melts and becomes foamy, tilt the pan and spoon the butter and garlic over the beef repeatedly for 30–60 seconds to glaze (baste). Remove the beef to a cutting board and tent loosely with foil. Rest for 8–10 minutes to allow juices to redistribute.

Slice & serve

Slice the beef thinly across the grain into 6–8 mm (1/4 inch) slices. Arrange on a warmed platter. Sprinkle chopped parsley and an additional small pinch of sea salt and black pepper. Optionally squeeze half a lemon over the slices for brightness. Serve immediately.