Bring a large pot of water to a boil. Add the noodles and cook for 1 to 2 minutes to warm through. Drain noodles and set aside.
In a large skillet, heat the sesame oil over medium-high heat. Add garlic, ginger, lemongrass, celery, onion, shallot, carrots, and vinegar. Cook 2 to 3 minutes until the onion is translucent and the mixture is fragrant.
Add broth, bean sprouts, scallions, mint, and chili paste. Cook for another 2 minutes.
Add the drained noodles and cook for 1 minute, tossing with tongs to combine.
Divide the noodles among 6 bowls. Season each serving to taste with salt and pepper and sprinkle with lime zest and juice. Serve hot.