- 1.
Soak the dried shiitake mushrooms in 4 cups of hot water for at least 30 minutes, or until softened. Reserve the soaking liquid, strain through a fine-mesh sieve to remove any grit.
- 2.
If desired, roast the onion, ginger, and garlic: Preheat oven to 400°F (200°C). Place the quartered onion, sliced ginger, and crushed garlic cloves on a baking sheet. Roast for 20-25 minutes, or until slightly charred. This step intensifies their flavor (Optional).
- 3.
In a large stockpot, combine the reserved shiitake mushroom soaking liquid, vegetable broth, sliced cremini mushrooms, rehydrated shiitake mushrooms (sliced), roasted onion, ginger, and garlic (if roasted; otherwise, add raw), star anise, cinnamon stick, and fennel seeds (if using).
- 4.
Bring the mixture to a boil, then reduce heat and simmer for at least 30 minutes, or up to 1 hour, to allow the flavors to meld. The longer it simmers, the richer the broth will be.
- 5.
Strain the broth through a fine-mesh sieve, discarding the solids. Return the broth to the pot.
- 6.
Season the broth with soy sauce, rice vinegar, brown sugar (or maple syrup), salt, and black pepper to taste.
- 7.
While the broth is simmering, prepare the rice noodles according to package directions. Usually this involves soaking them in hot water until softened, or briefly cooking them in boiling water.
- 8.
If using tofu, pan-fry or bake the tofu cubes until golden brown and crispy. (Optional)
- 9.
To assemble the pho, divide the cooked rice noodles among bowls. Top with bean sprouts, julienned carrots, and cooked tofu (if using).
- 10.
Ladle the hot mushroom broth over the noodles and vegetables.
- 11.
Garnish with fresh Thai basil, cilantro, green onions, and sliced jalapeño (if using). Serve immediately with lime wedges for squeezing.