Cut the firm tofu into 6 equal pieces.

Trim the root of the enoki mushrooms and separate them. Cut them in half. Trim the root of the green onions and cut into 4cm lengths.

Heat salad oil in a frying pan. Add ground beef and press lightly without stirring. Let it brown, then break it apart and stir-fry. Once the beef changes color, add sugar and mix well.

Add tofu, enoki mushrooms, and the seasoning mixture (sake, mirin, soy sauce, water). Cover with a lid and simmer on low heat for 5 minutes, occasionally turning the tofu.