Toast the cashews in a dry pan until pale golden. Cool and roughly chop.
Wash the romanesco broccoli and divide into florets.
Peel the kohlrabi and cut into wedges. Peel the ginger and cut into fine strips. Wash the chilli and cut into rings.
Wash the spring onions and cut into 3cm pieces.
Heat the oil in a pan and briefly fry the spring onions over high heat. Remove and set aside.
Reduce the heat. Add the kohlrabi and ginger to the pan and cook for 3-4 minutes, stirring, over a medium heat. Wash the tomatoes and add to the pan.
Add the chili and curry paste and cook briefly.
Pour in the stock and coconut milk and bring to the boil.
Cover and simmer over a medium heat for 5 minutes. Add the romanesco and simmer, covered, for 5-7 minutes. Stir occasionally. Juice the lime.
Add the spring onions to the pan, 2 minutes before the end of the cooking time. Season the curry with salt, pepper and 1 tbsp lime juice and sprinkle with the cashew nuts.