Cut the flank steak in half, against the grain. Then cut each half into very thin slivers. *Flash freezing the steak, to make it firm, makes the slicing process easier. If you have time, throw the flank steak in the freezer for 30 minutes before slicing.
Toss the flank steak strips with 2 tablespoons of cornstarch and set aside.
Chop the scallions, and separate into whites and greens. Then chop the red bell pepper, mince the garlic, and grate the ginger.
Set an extra-large skillet, or a wok, over high heat. Add 2 tablespoons of sesame oil to the skillet and swirl around to make sure it is completely coated in oil.
Once the skillet is hot, stir fry the beef slices until seared brown on all sides.
Move the beef slices to the side of the pan. Pour the remaining 2 tablespoons of sesame oil into the skillet, and add the scallion whites, red bell peppers, Chinese chilies, garlic, and ginger. Stir fry the vegetables for 3 to 4 minutes to soften.
Now, pour the cooking sherry over the top of the vegetables, followed by the soy sauce, black bean garlic sauce, black vinegar, and Szechuan peppercorns. Mix the sauce and vegetables into the seared beef, making sure it is coated on all sides. If the sauce seizes up too much, add 2 to 4 tablespoons of water to the sauce to loosen.
Once the sauce is to your desired consistency, stir in the peanuts, and scallion greens. Serve warm over steamed rice, or over cauliflower rice for a lower carb version.
Video
Notes
Beef stir fry recipes are great for meal prepping! Let cool completely, then store in an airtight container and keep in the fridge for up to 4 days.