Prep all ingredients.

Slice the flat iron steak into thin slices. Make sure to slice against the grain so that the beef is not chewy in the finished dish.

Combine the beef with the soy sauce, garlic, and ginger in a small tupperware or plastic bag. Let marinate for at least 30 minutes.

When ready to cook, bring a pot of water to a boil. Blanch the broccoli for 2-3 minutes, then remove from water and drain thoroughly. Set aside.

Drain the marinade from the beef, reserving the marinade for later (this will be the stir-fry sauce).

In a pan over high heat, add the avocado oil. Once hot, add the beef and stir-fry for 2-3 minutes or until browned. Once browned, remove from the pan, leaving any remaining oil in the pan.

Add broccoli into the pan and cook for another 2-3 minutes or until broccoli is crisp but tender. Add the reserved marinade liquid and into the pan and cook for another 1-2 minutes. Once you add the marinade into the pan, sprinkle xanthan gum over the liquid and stir to help thicken.

Place the beef back into the pan along with the fish sauce and toasted sesame oil to warm through.

Once everything is hot, serve immediately.