Cut the tofu into 2cm cubes then wipe them with paper towels to absorb excess water. Put them in a bowl, add 1 Tbsp soy sauce, the chilli flakes and combine.
Chop the ginger, spring onions and mushrooms.
Heat half of the oil in a wok, then stir-fry the tofu until golden brown on all sides. Transfer the tofu cubes to a plate, lined with kitchen paper towel.
Add the remaining oil to the wok, then stir-fry the ginger and spring onions for a minute. Add the shiitake and soy sauce, rice vinegar and mirin. Cook for 5 minutes, then add the edamame beans. Put a lid on and simmer for 3-5 minutes.
Serve warm with the crispy tofu cubes.