Peel the onion and carrot. Put half the onion, the sliced carrot and the chicken in a saucepan with enough cold tap water to cover, about 900 ml. Bring to a gentle simmer and poach for 20–25 minutes, or longer for thick breasts, until the chicken is cooked through. Check the thickest part reaches 75°C for at least 30 seconds. Lift the chicken onto a clean plate and shred with two forks. Strain and reserve the cooking broth.

Meanwhile, peel the potatoes, cut into thick rounds and boil in a separate pan for 12–15 minutes until tender. Hard-boil the eggs for 10 minutes, cool under running water, peel and quarter. Cook the rice following its packet instructions and keep hot until serving.

Tear the bread into a blender jug and add 250 ml of the hot chicken broth. Let it soften for 5 minutes. Add the walnuts and blend until smooth, taking care with hot liquid, or finely grind the nuts and mash everything together thoroughly.

Finely chop the remaining half onion and the garlic. Heat the oil in a wide saucepan and soften the onion for 8 minutes. Add the garlic, cumin and ají amarillo paste and stir over a low heat for 2 minutes without scorching.

Stir in the bread-and-walnut mixture. Add the evaporated milk, grated Parmesan, salt, pepper and shredded chicken. Simmer gently for 8–10 minutes, stirring and adding reserved broth in small splashes until the sauce is creamy and spoonable. Heat until piping hot throughout; do not leave a thick sauce unattended.

Divide the potato rounds and hot rice between four plates. Spoon the chicken sauce over the potatoes and finish each plate with two egg quarters and the drained, pitted black olives.