1. Wash and slice the beef, peel and slice the potatoes, and cut the tomatoes into small pieces.

2. Heat the oil pan, add appropriate amount of salt, add beef and stir-fry until white.

3. Add 2 tablespoons of tomato sauce and stir-fry twice. Add light soy sauce and potatoes. Add appropriate amount of water and simmer for a while to reduce the juice.

4. After the juice is reduced, add tomatoes and stir-fry for a few times before serving.