Tamales de piangua: Guapi plantain tamales with shellfish

Check and cook the piangua Keep live shellfish cold until cooking. Discard cracked shells and any shellfish that are open and do not close when tapped. Scrub under cold running water. Put the piangua in a large pot with enough water to cover; bring to a full boil and cook for 10 minutes. Remove the meat, discarding shells that did not open. Chop the meat, return it to fresh simmering water and cook for 30 minutes. Drain well. Keep the shellfish separate from ready-to-eat ingredients and wash hands, utensils and surfaces after handling raw shellfish.

Make the Pacific refrito Warm the achiote oil in a wide heavy skillet over medium-low heat. Add the long onions, yellow onion and garlic; cook until soft and fragrant without browning. Add the tomatoes, chillangua, poleo, 4 g salt and black pepper. Cook gently, stirring often, until the tomatoes collapse into a moist, spoonable sauce. Measure 240 ml for the masa and 120 ml for the filling.

Cook and mash the plantains Put the plantain chunks and coconut milk in a large heavy pot. Bring to a gentle simmer, cover partially and cook until a fork passes through the plantain easily, about 20 minutes. Lift out the plantain and mash or grind it while warm. Return it to the coconut liquid, stir in 240 ml refrito and 6 g salt, then cook over low heat, stirring frequently, until it forms a thick, soft masa that holds a spoon track. Do not let the coconut mixture scorch.

Finish the piangua filling Stir the drained, cooked piangua into a skillet with 120 ml refrito. Simmer for 10 minutes so the shellfish takes on the seasoning and the mixture stays moist but not soupy. Fold in the cooked potato. Keep the hard-boiled egg separate for assembly. If the filling was prepared ahead, chill it promptly and reheat it until steaming before wrapping.

Soften the leaves and assemble Briefly warm each banana leaf over a low flame or hot pan until flexible; wipe it clean and trim away any stiff rib. Set a leaf on the work surface and spread one eighth of the warm masa into a thick oval. Add one eighth of the piangua-and-potato filling and one quartered egg, then cover with a little more masa. Fold the leaf into a sealed parcel and tie it firmly with twine. Patch tears with an extra leaf; make 8 parcels.

Simmer the parcels Set a rack or spare leaves in the base of a large lidded pot. Add 3 litres water and 10 g salt, then arrange the tamales above the water line if using a rack; otherwise keep them partially submerged as the pot simmers. Cover and cook at a steady simmer for 60 minutes. Maintain the water level and add boiling water if needed. The leaf parcel protects the masa from direct agitation.

Check, serve and store safely Carefully open one parcel and check that its centre is steaming hot throughout; for a measurable check, the centre should reach at least 74°C. If it is cooler, retie the parcel and continue cooking, then check again. Serve hot in the leaves. Keep cooked tamales at 60°C or hotter if holding for service. Refrigerate leftovers within 2 hours in shallow containers at 5°C or colder and reheat until the centre reaches 74°C. Discard shellfish that failed to open during the first boil; do not taste it to judge safety.