Place a large pan or wok over medium heat. Add coconut oil along with minced garlic and grated ginger.
When garlic becomes fragrant, turn heat on low then add coconut aminos. Be sure that the pan has cooled down a bit before to keep the coconut aminos from splattering everywhere.
Once coconut aminos have been added, increase heat to medium-low and add honey, sriracha, sesame oil and fish sauce.
Bring sauce to a slow boil, then add 1 tablespoon of arrowroot powder, 1 teaspoon at a time and whisking to incorporate into the sauce. Meaning you will add 3 teaspoons total, whisking each teaspoon in at a time.
Once sauce has become think, add peppers, onion and sliced mushrooms to the sauce and coat in sauce. Let cook down for about 6-8 minutes or until onion is soft.
After the vegetables have cooked through, use a slotted spoon to remove the vegetable and set aside in a bowl.
Increase heat to medium-high temperature and add thinly sliced flank steak to the pan. Cook steak on both sides for 2-3 minutes, until barely any pink remains.
Add vegetables back into the pan and incorporate with the meat.
Since the meat will render some liquid, add the remaining tablespoons arrowroot powder into the mixture, teaspoon at a time, whisking the powder in with the mixture.