Bring a pressure cooker full of water to a rolling boil. Add the oxtail and brisket and return to a boil. Set the timer for 12 minutes after the water returns to a boil. Fill a large bowl with cold water and set it aside.

While the bones are boiling, put the onion and ginger on a sheet pan and place it cut side up directly under the heating element of your broiler. Broil until the onion and ginger are nicely charred. Watch carefully to ensure they don’t burn.

When the timer goes off, remove the oxtail and brisket from the pressure cooker and place into the bowl of cold water. Wash the bones thoroughly to remove any congealed blood, or other contaminants that can cause the soup to be cloudy. Wash the pot of the pressure cooker out well, and then place the bones and meat back in.

Place the cinnamon, star anise, fennel seeds, and cloves into a pan and toast on the stove, stirring frequently to prevent burning until the spices are toasted and fragrant.

Add the toasted spices to the pot with the brisket and bones and then add the cilantro roots and 8 cups of water. Seal the lid and bring the cooker up to high pressure. When it's at pressure, set the timer for 30 minutes.

When the timer goes off, use the quick release method to release the pressure from the cooker and open the lid when the pressure has released. Remove the brisket and quickly wrap it in plastic wrap to prevent the meat from drying out. Let it come to room temperature and then store it in the fridge until it’s time to use it.

Seal the lid of the pressure cooker again and bring the pot back up to high pressure. Continue cooking the broth for 45 minutes and then let the pressure drop naturally.

When the pressure has dropped, open the lid and use tongs to remove the oxtail. Set it aside until it has cooled and remove the meat from the bones. Use a fine mesh sieve to strain the solids from the broth, and then skim away most of the fat.

You should have 5 cups of stock. If you have less, add enough water to make 5 cups. If you have more than 5 cups, boil the stock down a little more to concentrate it.

Transfer the prepared stock to a large pot and add the fish sauce , adjusting to taste. Keep the broth warm over low heat.

Have all of your bowls, toppings, and condiments ready so the noodles don’t get soggy.

Slice the onion as thinly as possible and place in a bowl of water to soak. Slice the cooked brisket. Slice the tenderloin as thinly as possible.

Divide the noodles between the bowls and top with the sliced onions, cilantro, brisket and raw tenderloin. Bring the pho broth to a boil and divide it between the bowls. Enjoy with additional toppings and condiments.