In a large frying pan or wok, cook meat or tofu for 3 to 5 minutes.

If using beef or pork, use a fork to break into small chunks, and drain off fat.

Set meat or tofu aside.

Wash the pan and dry thoroughly.

Heat 1 tablespoon vegetable oil over high heat for 1 minute.

Add onions and stir-fry for 2 to 3 minutes, or until crisp-tender.

Add cabbage and continue to cook, stirring frequently, for another 2 to 3 minutes, or until cabbage is crisp-tender.

Add bean sprouts and green onion, mix well, and cook for 1 to 2 minutes more.

Remove the pan from heat and pour vegetable mixture into a colander to drain off excess liquid.

Return vegetables to the pan.

Add meat or tofu, salt, and black pepper, and mix well.