1. Steam the crabs for 8 minutes. Set it aside
2. Melt the butter in a wok and saute the chopped chilli and garlic until fragrant.
3. Add in the curry leaves and fry for a few seconds.
4. Pour in the evaporated milk, salt and sugar and simmer for a few seconds.
5. Put the steamed crabs back into the sauce and give it a good stir.
6. Dilute the corn flour with water and mix it into the sauce.
7. Let the sauce thicken and serve immediately.
8. Best served with hot rice and fried buns.