Wash and peel the sweet potatoes. Cut them into large chunks.
Bring a large pot of water to a boil and add the sweet potatoes. Cook them 10-15 minutes, until they are just underdone. Drain them and return them to the pot. Add the vegetable broth and bring to a simmer. Cook until they are very soft, about another 15-20 minutes. Puree them with a hand held blender, or in batches in a blender. Add the yellow curry paste and stir to combine. Add the chick peas, the tomato and the green beans. Return to a simmer and cook for 20 minutes.
Meanwhile, bring another pot of water to a boil. Add the cauliflower and cook until just tender, about 5 minutes. Drain and pat dry.
In a large skillet on the stove, mix the olive oil and curry powder over medium high heat. Add the cauliflower, the onion and the zucchini and cook 5 minutes. Do not let the vegetables brown. Add them to the pot with the potatoes, chick peas, tomato and green beans. Add the coconut milk, stir to combine and return to a simmer. Cook for a further 20 minutes.
In a small, heavy, dry skillet, lightly toast the cashews. Remove the curry to a serving platter and scatter the cashews and cilantro across the top. Serve over white rice.