Soak the dry shiitake mushrooms overnight in room-temperature water. If rush on time, soak in warm water until the mushrooms are soft and tender.
Pre-boil the bones and brisket: add the bones and brisket to a large stockpot and cover with water. Bring the water to a boil over high heat, then reduce to medium and simmer for 10 more minutes. Rinse the bones and meat over room temperature tap water. Set aside. Discard the broth.
Pan-grill the ingredients under “herb combo” in cast iron over medium heat with no oil added. Rotate and flip the ingredients frequently until you can smell a nice aroma. Take care not to burn the ingredients. A little charred outer surface is okay but not burnt.
Squeeze the mushroom to wring out the liquid, slice them, and save the mushroom water. Add the aroma combo and leeks to large tea bags.
Instant Pot:
In a 6-quart instant pot, add beef bones, brisket (with the fatty side up), mushroom, onion, carrots, and the herb combo in the tea bags. Strain the mushroom water through a sieve as you add the liquid to the pot. Fill the pot with more tap water until it reaches the 4-liter mark. Close the lid in the Sealing position - Press Soup - Adjust to 40 minutes/High pressure/More.
Allow the instant pot to come to natural pressure release (valve dropped), and discard the tea bags.
Carefully remove the brisket and soak it in cold water for at least 10 minutes. This will prevent the meat from turning a dark color. Discard the bones and the onion. Season the broth with salt, fish sauce, and five-spice powder, if using.
To serve:
If served with rice noodles, follow the package instructions to boil the noodles in a separate pot.
Prepare 4 large soup bowls. Add noodles, bean sprouts, chili peppers, mint leaves, baby bok choy, Thai basil, and cilantro to the bowls.
Thin slice the brisket at a 45-degree angle against the grain and add them to the bowls. Ladle the broth over each bowl. Serve hot with lime wedges on the side.
Video
Notes
The ingredient measurements and cooking time are written for a 6-quart instant pot. If your instant pot size is smaller than 6-quart, please reduce the beef bone and brisket quantity by a ¼ to ½ lb less. Please make sure not to overfill the soup pot. Leave some space to allow liquid to come to a boiling state without spilling over.
For a smaller size instant pot (smaller than 6-quart), adjust the quantity to 1 cup dry shiitake mushrooms, and 2 loose carrots, and season the broth with 1 ½ tsp coarse sea salt or to taste.
Pre-boil the meat/raw bones is an important step to produce a clear pho broth. The boiling process will remove the blood and other small bone fragments/impurities.
Use large tea bags to hold the aroma combo and leeks. It’s easier to discard them after cooking. If using cheesecloth tied with a string, be sure the cloth is not too thick so that the aroma flavor can come through.
If you follow the steps above, there’s no need to strain the broth after cooking. The broth should be clear (not muddy) and in beautiful golden brown color.
The popular condiments for pho are sriracha sauce and hoisin sauce. You can serve these sauces on the side. Personally, I prefer enjoying my pho without these condiments so that I can taste the original flavor of the delicious broth.