Defrost the langoustines in lukewarm water. Drain & dry them once defrosted
Cut some ginger, 2 garlic cloves and lemongrass. Cut the lemongrass into big chuncks and smash them down with the flat blunt edge of your knife for maximum flavour release
Heat up some olive oil in a pan. Add chopped ginger, garlic, chili flakes and lemongrass. Let this simmer until fragrant
Turn up the heat and cook the langoustines
Once halfway cooked add a small cup of coconut milk and let it simmer on medium heat. Cook out most of the liquid
Take out the big pieces of lemongrass, taste and add fish sauce and some lime juice. Taste once more and add salt & pepper if needed