Season the chicken with salt and pepper.
Heat the oil in a pan and fry the meat for 3 minutes on each side. Cover the base of the pan with a little hot water, cover and cook over a low heat for 4 minutes. Remove the meat and allow to cool.
Meanwhile, cook the egg in boiling water for 9-10 minutes until hard boiled. Cool under cold water, then peel and chop.
Wash the spinach, shake dry and tear into bite-size pieces.
Wash the tomatoes and remove the stalks. Deseed the tomatoes and cut into cubes.
Coarsely crumble the feta cheese.
Wash the chicory and cut into strips.
Juice the lemon. Halve the avocado, remove the stone, peel and cut into cubes. Mix with some lemon juice.
Cut the chicken fillet into cubes. Layer the prepared ingredients alternating into a bowl, and complete with chicken cubes and chopped egg. Add vinaigrette over the layered salad.