Thoroughly clean the chicken breast. Cut the meat with a knife about halfway to form a pocket. Fill the slice of chicken with brie and a teaspoon of black olive pâté, then close the stuffed chicken breast with a toothpick. Grease the pocket of stuffed chicken breast well with a trickle of oil and season to taste; to do this we use just salt and pepper. Grill the pocket of chicken breast for around 6/8 minutes, turning it over once or twice on each side. When the chicken breast reaches 74 °C (165 °F) in the middle, it will be ready. Once cooked, leave it to stand for 3 minutes then cut into slices of around 1cm and serve.