Cook the noodles according to the package instructions (typically 2-3 minutes if boiling). Drain and rinse thoroughly under cold water until fully cooled. Set aside (*note: some brands may only require soaking).
Heat the oil in a large pot over medium heat. Add the onion, mushrooms, and bell pepper. Sauté for 4-6 minutes until tender.
Add the garlic and ginger, and cook for 30-60 seconds until fragrant.
Add a splash of oil, then stir in the curry paste and tomato paste. Cook for 1-2 minutes, allowing the paste to darken slightly.
Pour in the vegetable broth, coconut milk, vegan fish sauce, and brown sugar. Stir well, scraping up any browned bits from the bottom of the pot. Increase the heat to bring the mixture to a boil, then reduce to a gentle simmer. Let it cook for 10 minutes, stirring occasionally.
Gently stir in the rice noodles and tofu, warming them through for 1-2 minutes.
Remove the pot from the heat and mix in the lime juice and cilantro. Taste and adjust the seasoning as needed.
Use tongs to divide the noodles among serving bowls, then ladle the soup on top. Garnish with additional cilantro and serve with lime wedges. Enjoy!