Lanzhou beef noodle soup

Clean the beef bones carefully, removing all bone dust.

Wash the pot and soak the bones and the piece of beef in cold water in the fridge overnight.

Next day, keep the beef soaking in the fridge in a container; pour off the red water and wash the bones again.

Put the bones in a clean pot, fill with water, cover and bring to a boil to blanch.

Once boiling and the impurities rise, discard the whole batch of water; rinse the bones, squeezing out any bloody parts, and wash the pot.

Return the bones, fill with about 4 liters of water, cover and bring to a boil.

Move to the lowest flame and simmer at least 3 hours, or overnight, with the lid slightly open; add water if needed.

Add the beef and simmer another 4 hours.

Take out the beef and cool it in the fridge for slicing. Skim the oil from the top of the broth with an oil strainer.

One hour before serving, add the halved onions, ginger, cinnamon, star anise, Sichuan peppercorn, black peppercorn and the cumin seed, toasted in a pan and slightly crushed; stir and simmer 1 more hour.

Slice the cooled beef thinly.

Cook the fresh noodles in a separate pot of boiling water 2 to 4 minutes, tasting to check; transfer to a serving bowl.

Season the bowl with salt and black pepper, pour in the broth leaving the spices behind, top with beef slices, scallion and cilantro, and chili oil if liked.

To store leftover broth, strain out small particles into containers, leaving space at the top so they do not crack; about 1.5 months frozen or 2 days in the fridge.