CLEAN: Add the clams to a bowl and cover them with cold water. Let them soak for 15 minutes, then pour off the water, and recover them with more cold water. Fill a second bowl halfway with cold water. Use a stiff brush or sponge to remove any sand or debris from each individual clam and then drop them into the second bowl with clean water. Once the clams have been cleaned, tap any open clams on the side of the bowl and watch to see if they close. Discard any clams that do not close. Put the cleaned clams into the fridge while you prep the rest of your ingredients.
PREP: Scrape the skin from the ginger root with the back of a spoon, then peel the garlic cloves and shallot. Use a mandoline to slice the ginger and garlic finely, then mince the shallot. Use the back of your knife to bruise the fresh lemongrass and remove the tough, woody outer layers. Stack the basil leaves on top of each other, then roll them together to slice them finely into strips.
SIMMER: Add the oil to the bottom of a large pan over medium heat – whatever you use needs to be large enough to add the clams to later and have a lid. Add the ginger, garlic, shallot and lemongrass to the pan and cook for a minute or two, until fragrant, stirring to avoid any burning or color change. Add the coconut milk, fresh basil, kaffir lime leaves, fish sauce and dried Thai basil (if using). Stir together and simmer gently on the stove top for 10 – 15 minutes, uncovered, to both infuse and reduce the coconut milk. Reducing the coconut milk down now means that it won’t end up too watery later when the clams are added and release extra water into the broth.
STEAM: Remove and discard the lemongrass and kaffir lime leaves. Drain the clams and rinse them to make sure you’ve gotten rid of any sand or grit, then add them to the coconut milk broth and cover the pan with a lid. Watch the heat to make sure that the coconut milk broth simmers but doesn’t boil and cook until the clams have opened. Uncover the pan, discard any unopened clams and stir through the fresh lime juice. Serve the clams in the broth, with thinly sliced radishes and green onions to garnish. Don’t forget to slurp up that broth with a spoon!
This recipe uses fresh Thai basil, but if you can’t find any where you live, I recommend adding some dried Thai basil to the dish along with the fresh basil leaves and some additional fresh mint.