01 - Combine steak cubes, soy sauce, sesame oil, mirin, salt, and pepper in a bowl. Let marinate for 10-15 minutes to infuse flavors.
02 - Heat your Blackstone griddle to medium-high temperature. Add 1 tbsp vegetable oil and spread evenly across the cooking surface.
03 - Place marinated steak pieces on the hot griddle. Sear for 2-3 minutes per side until browned and cooked to desired doneness. Remove steak and set aside on a plate.
04 - Add remaining vegetable oil to the griddle. Pour in beaten eggs and scramble until just set. Push cooked eggs to the side of the griddle.
05 - Add minced garlic, peas, and carrots to the griddle. Sauté for 2-3 minutes until vegetables are heated through and fragrant.
06 - Spread chilled rice across the griddle. Break up any clumps with a spatula and stir-fry with the vegetables and eggs for 3-4 minutes.
07 - Drizzle soy sauce evenly over the rice and add butter. Mix thoroughly until everything is hot, evenly combined, and coated with sauce.
08 - Return the seared steak to the rice mixture. Add sliced green onions and toss gently to incorporate. Serve immediately while hot, garnished with sesame seeds and additional green onions.