Heat the vegetable oil in a large pot over medium heat. Add the chopped onion and cook until translucent and soft.
Stir in the minced garlic and ginger, cooking until fragrant. Add the curry powder, turmeric powder, and chili powder. Cook for a minute or until the spices are well mixed with the onions.
Pour in the coconut milk and chicken or vegetable broth. Stir to combine and bring the mixture to a simmer.
Add the shredded chicken (or tofu) to the pot. Stir in the fish sauce (if using), palm sugar, and salt to taste. Simmer for 10-15 minutes to allow the flavors to meld.
While the soup simmers, cook the rice noodles according to package instructions. Drain and set aside.
To serve, place a portion of the cooked noodles into bowls and ladle the soup over them. Garnish with fresh cilantro, fried onions, sliced green chilies, and chopped scallions if desired. Serve with lime wedges on the side for added flavor.
Enjoy your meal!