Clean the crabs thoroughly and cut them into pieces. Crack the claws slightly to allow the flavors to penetrate.
In a small bowl, mix the tomato paste, ketchup, chili sauce, soy sauce, oyster sauce, and sugar. Set aside.
In a large wok or skillet, heat the vegetable oil over medium-high heat.
Add the finely chopped onion and stir-fry until translucent, about 3-4 minutes.
Add the minced garlic, grated ginger, and chopped red chilies. Stir-fry for another 2 minutes until fragrant.
Add the crab pieces to the wok and stir-fry for about 5 minutes, ensuring the crab is coated with the aromatic mixture.
Pour the sauce mixture over the crabs and stir to combine.
Add the chicken broth or water and bring to a simmer.
Cover the wok and let it cook for about 10-15 minutes, or until the crab meat is cooked through.
Stir in the cornstarch mixture and cook for another 2-3 minutes until the sauce thickens.
Slowly pour the beaten eggs into the wok, stirring gently to create a smooth, eggy texture in the sauce.
Transfer the chilli crab to a serving dish.
Garnish with chopped fresh cilantro.
Enjoy your meal!