• Cut the lemongrass in half lengthwise.

In a large sauce pot over medium-low heat, warm 1 tablespoon oil until hot but not smoking. Add the lemongrass, cinnamon stick, star anise, and as many of the chiles de arbol as you like; and toast, stirring occasionally, until fragrant, 3 to 4 minutes.
Add the ginger-garlic paste, season with salt and toast for about 30 seconds.
Add the vegetable stock, 3 cups water, and bring to a boil. Then, reduce to a simmer and cook until the broth is infused with the flavors of the seasonings, 10 to 12 minutes.
While the broth cooks, prepare the sesame seeds and the bok choy.

In a frying pan over medium heat, toast the sesame seeds until fragrant, 3 to 4 minutes. Transfer to a plate to cool. While the seeds toast, cut the bok choy in half lengthwise. Add 1 tablespoon oil to the pan, and heat until hot but not smoking. Add the bok choy and cook until crisp-tender, 4 to 5 minutes on each side.

Remove the chilies, lemongrass, cinnamon and star anise from the broth. Add the rice noodles and cook until al dente, 4 to 5 minutes.

• Cut the tofu into ¼-inch-thick slices.
• Trim the root ends of the scallions and cut crosswise into ¼-inch-thick pieces.
• Coarsely chop the cilantro.
• Cut the lime into quarters.

Add the tofu and edamame to the pho and cook, stirring occasionally, until the tofu is heated through and rice noodles are tender, 2 to 3 minutes. Season to taste with salt.

Transfer the pho to individual bowls. Top with the bok choy, garnish with the sesame seeds, scallions, and cilantro and serve with the lime wedges on the side.