- Heat olive oil in a large cast iron skillet over medium-high heat for 2 minutes. While oil heats, stir together cubed steak, black pepper and Italian seasoning.
- Add steak to hot skillet and sear for 5 minutes, turning steak bites after 2-3 minutes. Transfer to a plate.
- Reduce heat to medium. Melt butter in skillet and use a spatula to scrape up any browned bits on the skillet. Add minced garlic. Sauté for 1 minute.
- Add mushrooms and sauté for 3 minutes longer.
- Stir in Umami Joy Sauce and add steak back to skillet. Cook for 2 minutes longer.
- Serve hot garnished with chopped green onion.