Cook the rice noodles according to package instructions, then drain, rinse with cold water, and set aside in serving bowls.

In a medium pot, bring the broth to a boil over medium-high heat.

Add the lemongrass, galangal (or ginger), and kaffir lime leaves. Simmer for 5 minutes to infuse the broth with aromatics.

Stir in the Thai chili paste and add the mushrooms. Cook for another 2 minutes until mushrooms soften slightly.

Pour in the coconut milk and bring the soup back to a gentle simmer. Do not let it boil vigorously to prevent the milk from splitting.

Add the prawns and cook for 2-3 minutes, or until they turn pink and opaque.

Remove the pot from the heat. Stir in the fish sauce and fresh lime juice. Taste and adjust seasoning if needed.

Ladle the hot creamy soup and prawns over the prepared noodles and garnish with fresh cilantro before serving.