Place 100g walnuts in a food processor and mix to give a coarse crumb. Repeat with the mushrooms and mix into the walnuts.
Heat the oil in a large saucepan and fry the walnut mixture and garlic for 5 minutes. Add the spices and cook for 1 minute.
Stir in the tomatoes, tomato puree and both beans and cook gently for 10 minutes, stirring occasionally. Season and stir in the coriander.
Meanwhile, cook the pasta shapes in boiling water for 11-12 minutes, drain and stir in the chilli mince, transfer to a baking dish. In a small bowl, mix together the cheese, breadcrumbs and remaining 25g chopped walnuts and sprinkle over the dish.