In a bowl, soak the 1/2 cup raw cashews in 1 cup of water.
In a large saucepan, heat up oil and add in the onion and fry for 10 minutes, on medium heat. Keep stirring and let the onions caramelise.
Add in the garlic, ginger Garam Masala, cardamom, cumin, turmeric, chilli and ground coriander. Fry for a further 5 minutes. If the spices start to stick, add a little more oil.
Add the onion mixture and the cashews in water to a blender and blitz up to make a sauce.
Return the sauce to the pan alongside the potatoes, salt and lemon juice and cook on medium heat until the potatoes are almost tender. If the sauce is evaporating too quickly, add in a bit more water.
Add in the zucchini and the coconut cream to the pan. Cook until the zucchini has softened.
Stir through chopped fresh coriander, chopped toasted cashews and add a little more salt if necessary.
Serve with rice, naan or roti.