Seco de piangua, Guapi coconut and mangrove-clam stew

Keep the piangua cold and clean the shells Buy live piangua from an approved, traceable seller and refrigerate it until cooking. The shells should be intact and close when tapped; discard cracked or damaged shells and any bivalve that remains open. Scrub under cold running water. Keep the raw shellfish on a separate tray, and wash your hands, board and tools before handling cooked food. Do not taste or reuse a utensil that has touched raw shellfish without washing it.

Extract two coconut milks Grate the coconut flesh. Add about 450 ml of the warm potable water in stages, kneading the flesh and squeezing it through a clean cloth or fine sieve to collect the thicker first milk. Re-knead the pulp with the remaining water and strain for a lighter second milk. Keep the two extractions separate. Coconut size and yield vary; reserve the thick milk for the refrito and use the lighter milk a little at a time if the stew needs loosening.

Steam the piangua until the shells open Put the bivalves in a covered pot with a small splash of clean water. Bring to a steady boil and steam for about 10 minutes, checking as they cook; continue for up to 30 minutes if needed, until the shells open. Remove opened shells with clean tongs and discard any that remain closed. Let the piangua cool just enough to handle, then remove the meat with a clean pick and chop it. Check the thickest pieces with a food thermometer and make sure they reach 63°C. Keep the cooked meat separate from the raw shells and liquid.

Prepare the herb refrito Heat the oil in a wide, heavy saucepan over medium-low heat. Add 120 g of the green onion and the garlic; cook for 3–4 minutes, stirring, until softened but not browned. Stir in chillangua, poleo, oregano, basil and achiote. Cook for 1 minute until fragrant. Add about 250 ml of the thick coconut milk and a portion of the salt; simmer gently for 5 minutes to make a red-gold, aromatic sauce.

Simmer the chopped piangua in the sauce Add the chopped piangua and stir until coated. Lower the heat and simmer gently for 20–30 minutes, stirring occasionally, until the sauce reduces and the meat is tender. If the pan becomes dry before the piangua is tender, add a little of the lighter coconut milk or clean water. Avoid a hard boil, which can make small bivalve meat tough. Taste near the end and adjust the salt.

Check the final temperature and texture Stir through the thickest pieces and verify they are steaming hot; if needed, use a clean thermometer to confirm 63°C. The sauce should cling to the piangua, with no watery layer at the bottom. If it is still loose, simmer uncovered for a few more minutes, stirring so the coconut does not catch.

Rest briefly and finish with herbs Take the pan off the heat and rest for 3 minutes so the sauce settles around the meat. Scatter over the reserved green onion. If the stew thickens too much while resting, loosen it with a spoonful of the thinner coconut milk and warm gently.

Serve hot Spoon the seco de piangua into warm shallow bowls. Serve immediately with plain rice or cooked plantain on the side. Keep it hot until serving and do not leave cooked shellfish at room temperature.