Chop the crabs into 2. Transfer in a pan and add 2 – 3 cups water. Simmer for 5 – 10 minutes until half cooked. Set aside.
Pre-heat pan with oil and add butter. Sauté onion till soft and translucent then add garlic and ginger.
Add crab broth, evaporated milk, spring onion, celery, oyster sauce, brown sugar, black pepper and all purpose cream. Simmer for about 2 minutes.
Add half cooked crabs. Season with salt to taste if needed. Place a lid and continue to cook for another 10 minutes under low heat. Lastly, add white pepper, mix it well and remove from the heat.