First, make a curry paste. Place the onion, garlic, ginger, garam masala, coriander, turmeric, cumin, salt, chilli powder and chicken bone broth in a small food processor and process to a paste.
To make the curry, heat the oil in a large saucepan over a medium–high heat, add the curry paste and cook, stirring occasionally, for 2–3 minutes, or until fragrant.
Add the chicken, cauliflower and sweet potato and stir to coat in the paste. When nicely coloured add the tomatoes, broth and chickpeas and stir to combine. Cover, bring to a boil, then reduce the heat to low and cook, stirring occasionally, for 15–20 minutes, or until the sauce is slightly thickened, the chicken has cooked through and the vegetables have softened. Top the curry with the spinach and leave to wilt for 2–3 minutes before stirring through.
Meanwhile, dry-fry the cashews over a high heat for 3–4 minutes, or until golden brown, tossing frequently. Leave to cool slightly, then roughly chop.
Divide the curry between serving bowls and sprinkle with the toasted cashews and coriander leaves to serve.