Wash the tofu and mung bean sprouts thoroughly and prepare them.
Cut the tofu into bite-sized pieces.
Drizzle cooking oil in a pan.
Add the tofu to the pan and cook until golden brown.
Add the mung bean sprouts and onion, and stir-fry together.
Season with salt, pepper, and soy sauce to taste.
Once all ingredients are cooked, transfer to a plate and serve.