In a mixing bowl, combine the soy sauce, pineapple juice, minced garlic, brown sugar, ground ginger, dry ground mustard, and dried parsley. Use a whisk to blend the ingredients until the sugar dissolves completely and the marinade is smooth.
Place the ribeye steaks in a resealable plastic bag or a shallow dish. Pour the marinade over the steaks, ensuring they are well coated. Seal the bag or cover the dish and refrigerate for at least 1 hour, or up to 8 hours for maximum flavor.
When ready to cook, preheat your grill to medium-high heat. This ensures a beautiful sear and locks in the juices.
Remove the steaks from the marinade, allowing any excess to drip off. Discard the leftover marinade. Grill the steaks for about 4-6 minutes per side, depending on your desired doneness.
Once cooked, let the steaks rest for about 5 minutes before slicing. This allows the juices to redistribute throughout the meat, ensuring every bite is tender and flavorful. Serve with your favorite sides and enjoy the burst of teriyaki goodness.