Slice the Beef: Thinly slice 300 g sirloin steak against the grain. This technique ensures the meat stays tender when cooked.
Prepare the Onion: Cut ½ white onion into thin wedges. The smaller the pieces, the quicker they will cook.
Heat the Pan: Heat a wok or skillet over high heat and add a tablespoon of oil (vegetable or sesame oil works best).
Sear the Beef: Add the sliced beef to the hot wok in batches, being careful not to overcrowd the pan. Sear until browned, about 2-3 minutes. Remove the beef from the wok and set aside.
Sauté the Onions: In the same wok, add a bit more oil if necessary and sauté the onions until softened, around 4-5 minutes.
Combine Ingredients: Return the seared beef to the wok with the onions. Toss everything together and add your favorite sauce. A combination of soy sauce, a pinch of sugar, and a dash of sesame oil makes for a fantastic finish.
Stir-fry: Cook everything together for an additional 1-2 minutes, ensuring all ingredients are well-heated. Serve immediately with rice or noodles.