Place the chicken breasts into a suitable dish and drizzle the olive oil over massaging it all over.
In a mixing bowl, combine the herbs and spices and mix thoroughly.
Sprinkle the chicken with the spices/herb mix and rub into the chicken.
Place clingfilm over the dish and allow the chicken and spices/herbs to marinade ideally overnight. If not possible, at least 4 – 5 hours.
When ready to cook, remove the chicken from the fridge and bring to room temperature.
Heat a griddle/frying pan over a high heat adding a little drizzle of olive oil.
Add the chopped bell pepper, onion and celery to frying pan for a few minutes stirring frequently.
Add the chicken to the heated pan and cook for about 5 minutes each side turning halfway through. Add a little butter to baste the chicken throughout making sure it stays moist.
After about 10 minutes or so the peppers and celery should be softened, and the chicken cooked. You don’t want the peppers to be overly soft as they lose their form and texture.