01 - Toss the sliced beef with 1 tbsp coconut aminos or tamari and 1 tsp sesame oil in a bowl. Let marinate for 10 minutes at room temperature.
02 - Whisk together the remaining coconut aminos or tamari, rice vinegar, sesame oil, chili flakes, black pepper, and a pinch of salt in a small bowl until fully combined.
03 - Heat 1 tbsp avocado oil in a large wok or skillet over high heat. Add the marinated beef in a single layer. Sear for 1-2 minutes per side until browned but still tender. Remove beef to a plate and set aside.
04 - Add the remaining 1 tbsp oil to the pan. Add garlic and ginger; sauté for 30 seconds until fragrant, being careful not to burn them.
05 - Add the sliced cabbage and carrot if using. Stir fry for 3-4 minutes until the cabbage is just wilted but still retains some crisp texture.
06 - Return the beef to the pan along with the green onions. Pour in the prepared sauce and stir well to coat everything evenly. Cook for 2 additional minutes, stirring constantly, until heated through and flavors are combined. Taste and adjust seasoning as needed.
07 - Serve hot, garnished with extra green onions or sesame seeds if desired. Pairs well with cauliflower rice for a complete meal.