Cook the egg noodles according to package instructions. Drain and set aside.
Heat oil in a large pot or Dutch oven over medium heat. Add the chopped onions and cook until soft and translucent.
Add garlic and ginger, and cook for an additional 1-2 minutes until fragrant.
Add the sliced chicken to the pot and cook until browned on all sides.
Stir in the curry powder and turmeric powder. Cook for 1-2 minutes, stirring constantly to toast the spices.
Pour in the coconut milk and chicken broth. Stir to combine and bring to a gentle simmer.
Add fish sauce, soy sauce, tamarind paste (if using), and brown sugar. Adjust the seasoning to taste.
Let the soup simmer for about 15-20 minutes, or until the chicken is cooked through and the flavors are well combined.
While the soup simmers, prepare the toppings. Arrange bean sprouts, cilantro, green onions, fried onions, and crispy noodles on a serving platter.
To serve, place a portion of cooked egg noodles in each bowl. Ladle the hot soup over the noodles. Top with bean sprouts, cilantro, green onions, and fried onions or crispy noodles. Serve with lime wedges on the side.
Enjoy your meal!