In a medium-sized mixing bowl, combine the olive oil, parsley, cilantro, minced garlic, red wine vinegar, and red pepper flakes (or fresh red chili, if preferred). Add a pinch of kosher salt and a few grinds of black pepper. Stir thoroughly until well blended. Let the sauce rest for at least 30 minutes to allow the flavors to infuse. For a more robust taste, refrigerate it overnight and give it a good stir before serving.

Generously rub both sides of each steak with chopped rosemary, minced garlic, salt, and black pepper. Allow the seasoning to settle into the meat for a few minutes.

Heat a heavy-bottomed skillet—preferably cast iron—over medium heat. Add a small drizzle of oil to prevent sticking, followed by the butter. Once the butter is melted and begins to foam, place the steaks into the hot pan. If the skillet is too small to accommodate both steaks without crowding, sear them one at a time to ensure a proper crust forms.

Sear the steaks undisturbed for 4 to 5 minutes, until the bottom side develops a rich, golden-brown crust. Flip the steaks and continue cooking the other side, spooning the hot butter over the surface as it sears. This technique, known as basting, enhances flavor and promotes even browning.

Cook the steaks to your preferred doneness, then remove them from the skillet and transfer to a cutting board or serving plate. Let them rest for at least 10 minutes to allow the juices to redistribute before slicing.

To serve, slice the rib eye steaks against the grain and generously spoon the chimichurri sauce over the top. Serve warm, with extra sauce on the side if desired.