Using fresh homemade stock gives the best depth of flavour, but low-sodium store-bought broth works well too - just adjust salt at the end. Breaking the spaghetti helps it cook more evenly in the soup, and any sturdy leafy green can stand in for chard or kale. Aush blends Persian, Central Asian and South Asian culinary traditions. The yoghurt-mint topping is distinctly Persian, the noodle-lentil combination resembles Central Asian and Turkish soups, and the spiced meat and tomato sauce echoes elements of Indian curries. Aush reflects Afghanistan's multi-cultural culinary heritage.