Heat the oil in a large pot over medium-high heat. Add the onion and garlic and sauté for 3 minutes, or until softened.
Stir in the curry paste and cook for an additional 2 minutes.
Add the vegetable broth, coconut milk, brown sugar, fish sauce, ginger, cumin and chili flakes. Bring to a boil then reduce heat to low and simmer for 10 minutes.
Add the cooked noodles to the pot and simmer for an additional 5 minutes.
Remove from heat and stir in the lime juice. Serve hot.