In a mixing bowl, combine the chopped parsley, olive oil, red wine vinegar, minced garlic, red pepper flakes, salt, and black pepper. Whisk until well combined.

Preheat the grill to medium-high heat. Season the ribeye steaks with salt and pepper on both sides.

Place the steaks on the grill and cook for about 4-5 minutes on each side for medium-rare, or until desired doneness is reached. Use a meat thermometer to check the internal temperature (130°F for medium-rare).

Remove the steaks from the grill and let them rest for a few minutes. Serve topped with chimichurri sauce.