Prepare resting tray: Place a rack on a tray.
Oil and season tuna: Drizzle half the oil over the tuna. Smear over one side, then sprinkle with half the salt and pepper. Flip and repeat.
Heat skillet: Heat skillet (preferably a skillet with grille lines) over high heat until smoking hot. The hotter, the better!
Oil skillet (if required): If your skillet is not well-seasoned, brush skillet with olive oil or take pan off stove and spray with any oil.
Cook first side: Place tuna steak in the skillet and cook for 45 seconds.
Rotate for grill lines: Turn steak 45 degree. Continue cooking another 45 seconds.
Cook other side: Flip tuna carefully, then leave for 1 minute or until the internal temperature in the middle reads 48°C / 118°F.
Rest: Remove tuna from skillet and place on rack. Rest for 5 minutes – it will cool down almost to room temperature. This is desirable for easier slicing and better eating. Serve with a side of greens beans and a sweet potato!
