2. For chimichurri sauce, in food processor, add cilantro, oregano, and garlic. Pulse to chop. Do not mush.
3. In a small bowl, transfer the cilantro mixture.
4. Pour olive oil, and mix to combine.
5. Drop salt, red pepper flakes, lime juice, and vinegar. Mix well. Set aside.
6. For steak, in a flat dish, combine salt and crushed peppercorn.
7. Put steak in dish, and press it firmly into the salt and peppercorn mixture. Coat on both sides.
8. Place a cast iron pan on heat, pour oil and wait until smoking hot.
9. Place steak, and cook for about 4 minutes. Flip, and cook for another 4 minutes.
10.Pop it in oven, and cook for 2-7 minutes or until done as desired.
11.Remove pan from oven, tent it with foil, and allow it to rest for 5 minutes.
12. Serve hot steak with chimichurri sauce.
Do not crush the peppercorn too fine.
Steak piece should have an internal temperature of 120-125 degree for rare, 130-135 degree for medium rare, and 140-145 degree for medium.