Ginger-Lemongrass Broth with Noodles, Silken Tofu, and Broccoli

In a saucepan, combine broth, 3 cups water, onion, garlic, lemongrass, ginger, cilantro, whole chile, and sugar. Bring to a boil, then reduce heat to low and simmer, partially covered, 30 minutes. Strain, discarding solids; return broth to pot. Stir in fish sauce; season with salt.

Meanwhile, bring a pot of salted water to a boil. Add Broccolini and return to a boil; cook until crisp-tender, about 1 minute. Using tongs, transfer to a plate. Add noodles to pot and cook until just al dente, about 4 to 5 minutes for wheat noodles, 3 minutes for rice noodles. Drain.

Divide noodles among bowls. Add Broccolini to hot broth, then gently add tofu and heat through over medium. Spoon broth, Broccolini, and tofu over noodles. Garnish with herbs and sliced chile, and serve with lime wedges.