Causa limeña – layered ají amarillo potato terrine with tuna filling

1. Boil the potatoes in their skins in salted water for 25-30 minutes until tender, peel and press through a ricer while still warm – don't use a stick blender or it turns gluey.

2. Mix in the ají amarillo paste, the juice of two limes and the oil, salt and knead until you have a smooth, bright yellow, mouldable mixture; leave to cool.

3. For the filling, mix the drained tuna with the mayonnaise and very finely chopped red onion and season with the remaining lime juice; thinly slice the avocado and drizzle with lime juice, hard-boil the eggs.

4. Press a third of the potato mixture into a cling-film-lined rectangular tin (or a ring mould), top with avocado slices, then another layer of potato, then the tuna filling, and finish with the remaining potato.

5. Chill for at least 1 hour to set, then turn out and slice with a sharp, wet knife.

6. Garnish the top with egg quarters and black olives and serve cold.

Tip: Causa's name comes from the Quechua "kausay" (food, life) – in Peru every family has its own filling recipe: chicken, prawns or crab can go in too.