In a large bowl, combine all marinade ingredients. Separate the beef slices and add into the marinade. Mix everything slightly with your hands. Toss in the green onions, onions and carrots and combine well. Cover with plastic wrap, transfer to the fridge and marinate for about 1½ hours.
In a large skillet over high heat, heat until very hot, add 2 teaspoons sesame oil. Add the marinated beef and cook until no longer pink and slightly caramelized, flip and stir occasionally. If needed, cook in 2 batches and don’t overcrowd the skillet. Transfer the cooked meat to a serving plate. Serve immediately.
Notes
I got my beef in Asian supermarkets, like Japanese, Chinese or Korean. They are all pre-sliced. If you can’t find pre-sliced ones, you can cut it yourself. Freeze your beef for 1 hour or so. With a sharp knife, cut the beef across the grain into 1/8-inch slices.
Use a skillet that can get really hot, like cast iron or wok. That helps to cook the meat faster and gives a nice brown sear.