Rest the steaks at room temperature for 30 to 45 minutes. Pat dry.
Make the chimichurri: finely chop the parsley, oregano, garlic and chilli by hand. Stir in the vinegar, salt, pepper and olive oil. Rest while you cook.
Heat a heavy pan until smoking hot. Film with neutral oil. Salt the steaks generously, lay them in away from you.
Three minutes undisturbed. Flip once. Three minutes more.
Add the butter, smashed garlic clove and thyme. Baste for a final minute.
Pull the steaks at 52°C internal for medium-rare.
Rest under loose foil for 8 to 10 minutes. This is not optional.
Slice thickly against the grain. Spoon chimichurri over, finish with flaky salt, serve.