Place the cashews in a bowl. Cover with boiling water. Let soak for 30 minutes. Drain and discard water. Set nuts aside.
Meanwhile, in a pot, soften the garlic and shallots in the oil. Add the spices and cook for 1 minute, stirring constantly. Add the cauliflower, sweet potato and water. Bring to a boil. Cover and simmer for 15 minutes or until the vegetables are tender.
In a blender, purée the vegetables with the lemon juice and soaked cashews until smooth. Season with salt and pepper. Keep warm.
In a pot of salted boiling water, cook the macaroni until al dente. Reserve ½ cup (125 ml) of the cooking water. Drain the pasta and return to the pot. Add the vegetable sauce and mix well to coat the macaroni. Add the reserved cooking water to thin out the sauce, if necessary.
In a small food processor, finely chop all of the ingredients.
Serve the macaroni in bowls. Garnish with the topping.