Trim legs and whiskers, and cut a slit along the back of the prawns. De-vein and wash thoroughly. Pat dry. Add a sprinkling of salt, lightly toss and set aside.
Fill a wok 1/4 full with oil. Heat over high heat till just smoking hot. Deep fry the prawns for about 30 seconds, or less, till just cooked through. Do be careful not to overcook the prawns. Dish out and drain on paper towels. Wash the wok clean and dry.
Meanwhile, mix cereal with seasonings, and stir well. Mix egg yolks with evaporated milk, and stir well.
Place butter in the wok and heat up over low heat. When butter has melted and begins to bubble, slowly pour in the egg yolk mixture and keep stirring until the mixture resembles fine threads. Add the curry leaves and cut chilli, continue to stir-fry over low heat. Add the cereal mixture (the cereal will absorb the butter and moisture from the curry leaves), and continue to fry till cereal is crisp and light. Add the prawns and toss to coat well. Dish out onto a serving plate and serve immediately.