Heat oven to 220C/fan 200C/gas 7. Beat the olives or sundried tomatoes, garlic and almost all the herbs into the cheese, then season. Cut a slit along the side of each chicken breast, then use your knife to open it out into a pocket.
Stuff each breast with a quarter of the cheese mix, then press to close. Lift onto a greased baking tray. Season the top of the chicken, then overlap tomato slices over the top of each piece of chicken. Season, then scatter with the remaining herbs. Drizzle with olive oil.
Roast for 20 mins until the chicken is golden around the edges and the tomatoes look a little shrivelled. Serve with a green salad and crusty bread to mop up the juices.
