Add the steak to a mixing bowl and season with salt and pepper. Stir until well combined.
Heat a large skillet over medium-high heat. Once the skillet is hot, you can add in the ghee. Next, add the steak bites to the skillet cook for 3-5 minutes until browned on all sides. Remove the meat from the pan and set aside.
Add the apple cider vinegar to the skillet to deglaze the pan. Then, add the minced garlic, onion, mushrooms, and diced peppers. Cook the veggies for 10-12 more minutes until the sliced onion is translucent and the bell peppers are tender yet crisp.
Add the steak and its juices back to the skillet. When the beef is back in the pan, give everything a good stir until well combined and cook for 2-3 more minutes until the steak is hot.
Remove the skillet from the heat and garnish with fresh sliced green onion before serving.