Thin slice the beef against the grain to less than ¼-inch thin. Combing and gently mix well the beef with all ingredients under ‘beef and marinade’. Set aside in the fridge. Prepare garlic, ginger, scallions, chili peppers (if using), bell pepper, basil, and set aside ‘stir-fry sauce’.
In a well heated large stainless steel skillet (or cast iron), add 2 tbsp cooking fat. Try to sear the beef over medium-high heat in one layer so they aren’t overlap with each other too much in the skillet. Sear the first side without disturbing for roughly 2 minutes or until golden brown then sear the flip side about 1 minute. Set aside in a large bowl along with the pan juice.
Use the same skillet, add 2 tbsp cook fat, saute garlic, ginger, white parts of scallions, and chili peppers. Season with a pinch of salt and saute until fragrant (about 10 seconds) over medium to medium-high heat. Add sliced bell pepper, season with another pinch of salt. Saute for 5-8 seconds. Add Italian basil and use the heat to extract the basil fragrance/oil. Saute for 5-6 seconds. Add beef back to the skillet and the ‘stir-fry’ sauce. Give a quick toss this dish is ready!
Serve the dish over cauliflower rice, broccoli rice, lightly sauteed zucchini noodles or steamed rice for a gluten-free meal.
If use Asian/Thai basil, add them at the beginning of Step 3 to saute with the garlic, ginger, scallions...etc. The texture of Asian/Thai basil is more sturdy and has stronger fragrant than Italian basil. They can take more heat in stir-fries.