Peel, de-vein and wash prawns thoroughly under running water. Drain and pat them dry. Peel and crush half the garlic cloves and roughly chop the rest.
Add one and a half cups of warm water to scraped coconut, grind and remove coconut milk. To make the red curry paste, grind together onion, garlic, red chillies, lemon grass, coriander seeds, cumin seeds, black peppercorns and salt to a fine paste.
Take prawns in a bowl. Add salt, one tablespoon of lemon juice and one tablespoon of red curry paste and mix. Add half the crushed garlic, half a tablespoon of fish sauce and mix.
Heat oil in a pan and add the remaining crushed garlic, fresh red chillies, marinated prawns and sauté for two minutes. Add a little water and bring to a boil. Add the remaining red curry paste and bring to a boil again.
Add coconut milk, salt, sugar and mix. Add lime leaves, the remaining fish sauce and mix. Add basil leaves torn with hands and the remaining lemon juice. Mix and serve hot.