Make the chimichurri first. Add the parsley, cilantro, garlic, oregano, red pepper flakes, salt, and pepper to a food processor or blender. Pulse until finely chopped. With the machine running, drizzle in the olive oil and red wine vinegar until the chimichurri comes together into a loose, slightly chunky sauce. Taste and adjust salt, red pepper flakes, or vinegar as needed. Set aside at room temperature.

Remove the steaks from the refrigerator 30 minutes before cooking to bring them to room temperature. Pat completely dry with paper towels.

Drizzle both sides of each steak with olive oil and season generously with the Buttery Steakhouse seasoning, salt, and pepper. Press the seasoning firmly into the surface of the meat.

Heat a large cast iron skillet over high heat until smoking hot. Add the butter and let it foam. Add the steaks and sear without moving for 3 to 4 minutes until a deeply browned crust develops on the first side. Flip and sear for another 3 to 4 minutes for medium rare, or longer to your preferred doneness.

Transfer the steaks to a cutting board and let rest for 5 to 10 minutes before slicing.

Slice against the grain and spoon the chimichurri generously over the top. Serve immediately with extra chimichurri on the side.