In Lanzhou, capital of Gansu, the day starts at a noodle shop where cooks stretch dough into strands before your eyes and drop them into bowls of clear, fragrant beef broth. Locals describe the ideal bowl in five colours: clear broth, white radish, red chilli oil, green coriander and garlic shoots, and yellow noodles. The broth is light yet deeply beefy and gently spiced, the radish sweet, the chilli oil toasty rather than fierce. This version uses good bought noodles, with an optional route for pulling your own if you fancy the challenge. Chef's tip: simmer the broth, never boil it; a hard boil turns it cloudy and the clear, golden look is the whole point.