Heat the coconut oil over medium heat and fry the laksa paste for 1-2 minutes.
Add the kaffir lime leaves, lemongrass and Thai chilies and cook 1-2 minutes.
Add the fish sauce, coconut sugar and fish stock and bring to a simmer for 5 minutes.
Add the coconut milk and simmer for 10-15 minutes, until slightly thickened.
Add additional salt or fish sauce to taste.
Add the prawns, cover, turn off heat and let it sit for 5-10 minutes, until prawns are cooked through (no longer pink/bluish).
Serve over rice noodles with bean sprouts, cilantro, fried garlic and fresh lime juice.
Notes
For a spicier soup, just add more laksa paste or Thai chilis. For a less spicy soup, cut back on the amount of Thai chilis.
If the soup is too sour or tangy, add a little more sugar.
If you can’t find prawns, you can substitute shrimp. You can also use cooked chicken, fish balls or fried tofu puffs.
Be careful not to overcook the prawns in the soup as they will get tough. Once they're no longer pink or bluish, they’re cooked.
Don’t add the noodles to the soup as they will soak up the broth and get mushy. When ready to serve, just ladle the broth over the noodles and store separately if you have leftovers.
If you’d like to minimize the coconut flavor but still keep the creamy texture, you can substitute evaporated milk for some of the coconut milk.
For a traditional laksa, you can cut the cooked noodles into 2-3" pieces so they can be scooped into a soup spoon.