Remove the steak from the refrigerator in advance (half an hour beforehand) so that it comes to room temperature. Then spread it on both sides with olive oil, salt and spices.
Melt butter in a frying pan and add steak. For medium, cook steak for 3 minutes on one side. Turn the steak over to the other side, adding extra butter if desired. Also add thyme sprigs to the pan.
Fry the steak for another 3 minutes, spooning the melted butter over the top constantly. Place the steak on foil and wrap it tightly. Leave for 10 minutes. Cut the steak into thin strips and serve with any sauce. You can also put an extra piece of butter on top.
Notes
RareInternal Temperature: 120°F to 125°F or 49°C to 52°C
Medium-RareInternal Temperature: 130°F to 135°F or 54°C to 57°C
MediumTemperature: 140°F to 145°F or 60°C to 63°C
Medium-WellInternal Temperature: 150°F to 155°F or 66°C to 68°C
Well-DoneInternal Temperature: 160°F and above or 71°C and above