Heat the cooking oil in a cooking pot.
Saute the garlic and ginger.
Add the onion. Cook until the onion becomes soft.
Add-in the crabs. Pour-in the fish sauce and add water . Let it boil.
Cover and simmer for 15 minutes.
Sprinkle some ground black pepper. Let the water reboil. Cook for 1 minute.
Put-in the misua noodles. Stir and cook for 1 minute.
Add the spring onions. Cook for 1 to 2 minutes more.
Transfer to a serving bowl.
Serve and enjoy!