Preheat your oven to 425 degrees. Lay your marrow bones and oxtail on a sheet pan. Roast for 20 minutes, then flip them over and roast for an additional 20-25 minutes.

On a second tray, toss the onion, green onions, garlic and ginger in a spray of avocado oil. Roast for 15-20 minutes.

In a small skillet, toast the coriander, peppercorns, cinnamon and star anise for about 1 minute over medium heat, or until fragrant.

Once the bones and vegetables are roasted, place them all into an instant pot. Add the toasted spices, coconut aminos, and coconut sugar. Pour in 6-7 cups of water, or until the liquid is halfway between the ½ and ? fill lines. Secure the lid on the Instant Pot and set it to the Soup/Stew Function. Set the Instant Pot to high pressure for 1 hour 45 minutes. After the pot finishes cooking and beeps, allow it to naturally release for 20 minutes. Allow the broth to cool slightly, then strain the broth into containers. Reserve any meaty bits from the oxtail for the soup or other purposes.

At this point, you can either refrigerate the broth to let the fat separate from the broth, or immediately use it. If you refrigerate, refrigerate overnight and pick off the fat layer that forms at the top of the broth. Place the broth in a pot and bring it to a boil. Allow it to simmer for a few minutes.

Very thinly slice your beef. You may find it easier to freeze the piece of beef for a few minutes to help it firm up and be easier to slice. Traditionally, you pour the hot broth over the beef which partially cooks it, but you can also place the beef into the simmering soup for a short amount of time to cook it more if you’d like. Arrange your bowls with your beef, noodles of choice, and any other add ins, such as cilantro, basil, mint, daikon radish, and scallions. Feel free to add in any red pepper flakes, sriracha, coconut aminos or fish sauce to taste.