In a medium bowl, combine the sliced beef, soy sauce, avocado oil, and cornstarch. Toss to coat and set aside to marinate.
In a separate bowl, whisk together all sauce ingredients until smooth. Set aside.
Heat 1 tablespoon of avocado oil in a large skillet over high heat. Add the beef and cook for about 3–4 minutes, stirring occasionally, until mostly browned.
Add the broccoli florets to the pan. Stir and cook for another 2–3 minutes until they start to soften.
Reduce the heat to medium. Stir the sauce again and add it to the pan. Let everything simmer for 2–3 minutes until the sauce thickens and the beef is fully cooked.
Serve hot over steamed rice or noodles.