With the help of a pestle and mortar, pound the white peppercorns with the salt and the garlic clove.
Add the basil and cilantro and pound again until it reaches a paste consistency.
Place the squid in a bowl and combine with the herb marinade. Let stand at room temperature for 15 minutes.
Heat the cooking fat in a large wok at a very high heat and cook the squid very quickly, about 30 seconds. Proceed by two batches if your wok is too small to cook the squid all at once very rapidly.
If you proceed by two batches, return all the squid to the wok, add the fish sauce and cook for a further 20 seconds. Serve while still hot.