01 -
Cut the sirloin into thin 1/2-inch strips against the grain. For easier slicing, chill in the freezer for 20 minutes until firm.
02 -
Whisk together soy sauce, sugar, cornstarch, and ground ginger until smooth and fully dissolved.
03 -
Coat beef strips in the marinade and let rest 15 minutes at room temperature or up to 2 hours refrigerated.
04 -
Heat 1 tbsp oil in a wok over high heat. Cook beef in small batches for 3 minutes until caramelized but still tender inside. Remove and set aside.
05 -
Add remaining oil to the wok. Stir-fry red onions for 2 minutes until slightly softened but crisp.
06 -
Toss in the green bell pepper and stir-fry for 2 minutes, keeping them bright and crunchy.
07 -
Add tomato wedges and return beef with juices to the wok. Toss for 1–2 minutes until tomatoes release juices and sauce thickens.
08 -
Transfer to a serving plate and garnish with green onions if desired. Serve hot with steamed rice or noodles.