Clean the coconut crabs thoroughly and cut them into large pieces. Set aside.
In a large pot or skillet, heat the vegetable oil over medium heat.
Add the finely chopped onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic and ginger and cook for another minute.
Add the ground turmeric, ground cumin, salt, and black pepper to the pot. Stir well to combine.
Pour in the coconut milk and water, stirring to create a flavorful sauce.
Add the crab pieces to the pot, ensuring they are submerged in the coconut milk mixture.
Bring the mixture to a boil, then reduce the heat to low and cover the pot.
Simmer for about 20-30 minutes, or until the crab is cooked through and the flavors are well combined.
Stir in the lime juice and adjust the seasoning with more salt and black pepper if needed.
Transfer the coconut crab to a serving dish.
Garnish with chopped fresh cilantro or parsley.
Enjoy your meal!