Heat oven to 200C/fan 180C/gas 6. Tear the bread into big, ragged croutons or, if you prefer, cut with a bread knife. Spread over a large baking sheet or tray and sprinkle over 2 tbsp olive oil. Rub the oil into the bread and season with a little salt if you like (sea salt crystals are best for this). Bake for 8-10 mins, turning the croutons a few times during cooking so they brown evenly.
Rub chicken breasts with remaining oil, season. Place pan over a medium heat for 1 min, until hot, but not smoking. Lay the chicken on the pan (it will sizzle if it’s hot enough) and leave for 4 mins. Turn the chicken, then cook for 4 mins more. Check if it’s cooked by poking the tip of a sharp knife into the thickest part; there should be no sign of pink and juices will run clear.