1. Mix the sauce ingredients in a small bowl and set aside.
2. In a very large pot of boiling water, parboil the crab for 3 minutes. Take out of the water and drain. Rinse the crab with cold water and drain again.
3. Pull off the top shell in one piece and reserve for additional garnish.
4. Remove and discard the gills and the spongy parts under the shell.
5. Twist off the claws and legs; crack them with a cleaver or a mallet. Now cut the body into 4 pieces.
6. Now in a large heated wok, add oil and swirl to coat the sides of the wok. add the garlic, ginger, and chili, and stir fry for 1 minute.
7. Add the crab, and stir fry an additional 2 minutes. Now add the sauce, reducing the heat to low. Cover and simmer, stirring once or twice, till the crab is cooked (6-7 minutes).
8. Finally stir in the egg and cook just until it begins to set (1 minute).
9. Arrange the crab and top shell on a large platter. Pour the sauce all over the crab and garnish with the green onion.
10. Serve right away with crusty bread to soak up the sauce.