Step 1

Press the Instant Pot's saute button until the highest setting is selected. Add olive oil to the insert of the Instant pot, then add in the quartered onion. Saute until dark brown—practically charred—in spots, about 5 minutes. Add the anise pods, cinnamon stick, fennel seeds, coriander seeds, and black peppercorns. Continue to saute for an additional 2 minutes. Press "Cancel" on the Instant Pot's control panel.

Step 2

Add 8 cups of water to the insert of the Instant Pot; use a wooden spoon to scrape up any browned bits on the bottom. Add the remaining ingredients for the stock. Close the Instant Pot's lid and seal the valve. Press "Pressure Cook" so that the highest setting is selected. Use the "+" button to adjust the time to 30 minutes. When the cook cycle is finished, allow the Instant Pot to depressurize naturally, about 25 minutes (or until the float valve drops).

Step 3

Once the Instant Pot has depressurized, press "Cancel." Twist open the valve and then the lid. Fish the solids out of the stock with a skimmer and remove to a colander set into a bowl. Rinse with 2 cups of water. Squeeze the mushrooms to get as much liquid out as possible. Discard the solids and add the rinsing liquid back to the Instant Pot. Run the stock through a fine-mesh strainer and into a bowl.

Step 4

Rinse and wipe out the insert of the Instant Pot, then replace in the cooker. Return the stock to the insert. Press "Saute" and choose the highest setting. Simmer the stock with sliced onions and cilantro stems for 10 minutes (meanwhile, prepare the pho noodles according to package directions). Next, add the sliced mushrooms and broccoli florets. Simmer for 5 minutes. Add the remaining vegetables and simmer long enough to soften up the baby bok choy and warm everything through, about 3 more minutes (see Recipe Note #4).

Step 5

Finally, divide the noodles among four bowls, add the stock and vegetables, and let everyone top with their favorite garnishes and sauces.