Chop the steak into 2-inch chunks.
Heat the avocado oil in a large (12-inch) skillet over medium-high heat. I like using my cast iron skillet to get a nice crust.
Add the chopped sweet potato and red onion. Stir well, then cover the skillet and cook for 4 minutes, stirring occasionally, until the veggies begin to soften.
Stir in the remaining ingredients: bell pepper, garlic, steak, and liquid aminos, arranging everything in a single layer if possible and cover again. Cook for 7 to 8 minutes, stirring occasionally, until much liquid is seeping out of the ingredients.
Remove the cover and continue cooking until much of the liquid has evaporated and there’s a sear on the steak, about another 5 minutes.
Serve in bowls with fresh chopped green onion and enjoy!