Heat the oil in a pot. Cut the shiitake mushrooms in half and fry them for a few minutes. Deglaze with vegetable stock. Peel the banana and cut into thin slices. Add to the mushrooms together with the sugar. Peel ginger and grate finely. Finely chop the chili pepper. Add ginger, turmeric, curry paste, coriander and chili pepper and bring to a boil. Add cauliflower and corn cobs cut into small pieces. Top up with coconut milk and simmer gently for about 10 minutes.
Season to taste with salt, pepper and lime juice. Clean the spring onions and cut into fine rings.
Arrange the cauliflower curry on plates and sprinkle with the spring onions.