Wash 4 pounds of beef bones to remove any bone dust. It is best to do a mix of all different cuts of bones.

Soak the bones and the beef meat with cold water. Let this sit in the fridge overnight.

Next day, the water becomes red and the meat has less color. Put the meat in the container and keep soaking it in the fridge. Pour the bloody water out and wash the bones again. Put the bones in a clean pot and fill it up with water. We are going to blanch the bones.

Cover this and bring the water to a boil. Once it comes to a boil, you will see a lot of impurity floating on the top. Those are the things that will affect the flavor and the texture of the broth. That is why we are going to get rid of this whole batch of water. You don’t need to worry about wasting all the flavor. The good stuff won’t come out in the first 10 minutes of boiling. Wash the bones again. Put the bone back and fill it up with water.

Cover it and bring this to a boil. Then simmer this for at least 3 hours. If you want to do it overnight, you can. But you want to put the lid slightly open. You don’t want it to be fully covered.

This is 3 hours later and I am going to add the beef. The reason I didn’t add the beef from the beginning is that after 3 hours simmering, the broth is pretty rich now and if you cook the beef in the broth, it will taste better.

Keep simmering this for another 4 hours. Then take out the beef meat. Cool it down in the fridge so it will be easier to slice it. Now you can check out the broth. Normally, there will be some oil floating on the top. You can take that out. The broth is very rich now but for making authentic Lan Zhou la mian, the broth needs some aroma. You want to add the spices 1 hour before serving. In this way, you can get the maximum fragrance out of it. I will add 2 medium-size onions, cut them in half. 4 slices of ginger, 1 pieces of cinnamon, 4 pieces of star anise, 1.5 tsp of Sichuan peppercorn, 1.5 tsp of black peppercorn, 2 tsp of toasted cumin seed. Give this a stir. We will keep simmering this for another 1 hour.

1 hour later, the broth is ready. I just keep it on the stove like that so it doesn’t get cold. Now you can start making the noodles.

Take the beef meat out and slice it thinly. Also, prepare some chili oil, diced green onion, cilantro and some noodles.

Cook the noodles in boiling water for 2-4 minutes. Take out the noodles and put it in a serving bowl. Add some salt, black pepper to taste, diced scallion and cilantro. put some slices of beef on top of the noodles and pour the broth into the bowl. If you like spicy food, you can add some chili oil.

That’s it. you have your authentic Lan Zhou beef noodle soup. Enjoy!