Heat the oil in a large pot over medium-high heat. When hot add the onion, garlic and ginger. Sauté until the onion softens and turns translucent, about 5 minutes. Stir in the curry paste, and continue to stir and cook for another 30 seconds until the curry is fragrant.
Pour in the vegetable broth and add the bok choy. Bring to a simmer and cook for 2 – 3 minutes until the bok choy starts to wilt. Add the rice noodles and cook another 2 – 3 minutes until the noodles are tender. Lastly, stir in the coconut milk.
Divide the soup among bowls, and add the toppings to taste.
If the noodles absorb too much broth, feel free to add water to thin out the soup as needed.