Causa Limeña

Method

1. 1Boil the potatoes whole and unpeeled in salted water for 25 to 30 minutes, until a knife slides out without lifting the potato. Cooking them unpeeled keeps them from taking on water, which is the difference between a dough you can shape and a wet paste.
2. 2Drain and peel them while they are hot enough to be awkward to hold, then push them through a ricer straight away. Never use a blender or food processor: the blades rupture the starch cells and turn the potato into something closer to glue. Spread the riced potato out and let it cool to room temperature.
3. 3Work in the ají amarillo paste, lime juice, oil and salt, kneading 2 to 3 minutes until the colour is even and the dough holds a shape when pressed. Taste it now and season it more assertively than seems right, since chilling flattens both salt and acid.
4. 4Shred the chicken finely and mix it with the mayonnaise and a pinch of salt to a thick, scoopable filling. If it is loose enough to spread on its own, it will slide when you cut the causa, so keep it firm.
5. 5Line a ring mould or a small loaf tin with cling film. Press in half of the potato dough in an even 1.5 cm layer, cover with slices of avocado brushed with lime, then the chicken layer, then the other half of the dough, pressing firmly at each stage to drive out air pockets.
6. 6Cover and refrigerate at least 2 hours, ideally 4, so the layers set and the flavours come together. Unmould by lifting the film, then peel it away rather than sliding the causa off it.
7. 7Finish with a thin spread of mayonnaise, wedges of hard-boiled egg, black olives and coriander, and serve cold within an hour of unmoulding, straight from the fridge rather than left to warm on the counter.