Remove the steak from the refrigerator 30 minutes before grilling. Pat it dry, brush with walnut oil, and season with a pinch of salt.
Preheat the grill (coal or gas) to high heat, 200-250°C (400-480°F).
Grill the steak on both sides for 2-3 minutes over direct heat. Move the steak to indirect heat and continue grilling until the internal temperature reaches 52-55°C (125-131°F).
Remove the steak from the grill, wrap it in foil, and let it rest for 5-10 minutes. Season with salt and pepper to taste, cut, and serve with herbal butter or a sauce (optional).