Add the vegetable broth, onion, garlic, ginger, turmeric, star anise, and cinnamon stick to a large pot. Bring to a boil, then reduce heat and simmer for 25 minutes.
Strain the broth into a clean pot and stir in the soy sauce. Keep warm over low heat.
Cook the rice noodles according to package directions, then drain and divide among four bowls.
Heat the neutral oil in a skillet over medium heat. Add the tofu cubes and cook until golden on all sides, about 6 to 8 minutes.
Place tofu on top of the noodles in each bowl. Ladle hot broth over everything.
Add bean sprouts, cilantro, green onions, and lime wedges to each bowl just before serving.