In a food processor, combine the parsley, oregano and thyme and pulse until everything is chopped.
Add the garlic and pulse a few more times until the garlic is chopped and mixed with the herbs.
Transfer the mixture to a bowl and add the salt, the red pepper flakes, the cumin, the pepper, the lime juice, the vinegar and the olive oil.
Stir everything together and your chimichurri sauce is ready.
Preheat your oven to 400 degrees.
Season your steak with salt and pepper on both sides
In a cast iron skillet, heat some olive oil over high heat until piping hot.
Sear the steak for 5 minutes on each side or until golden brown.
Transfer the cast iron with the steak to the oven and finish cooking for 5 more minutes (or more if you want your steak well done).
Let the steak rest for 10 minutes before slicing.
Serve the steak with the chimichurri sauce.