Dice the tofu and fry the cubes until golden all over (alternatively bake them in the oven at 180°C). Set aside.
Cook the noodles according to the package instructions, then drain and cover in the saucepan.
Finely slice the cabbage and chop the spring onions.
Heat the stock in a saucepan, add the cabbage and cook for 5 minutes.
Mix the Miso paste in a small bowl with a ladleful of the stock until smooth, then add to the soup. Add the tofu and cook for another couple of minutes.
Divide the noodles between two or three bowls, then ladle the soup on top. Garnish with spring onion and serve with a dash of lime juice.