Place the chicken breasts between two sheets of cling film and beat with a rolling pin or the flat side of a meat mallet until it is about 1cm thick.
Lightly season with pepper.
Heat the oil in a large frying pan and gently sauté the garlic, pancetta and sage over a medium heat until the pancetta is crispy.
Remove from the pan with a draining spoon, set aside and keep warm.
Increase the heat and add the chicken breasts. Fry for about 3 to 4 minutes each side until the chicken is browned on the outside and cooked through - the juices should run clear when pierced with the tip of a sharp knife.
Return the pancetta, garlic and sage back to the pan toss over the heat for a few seconds. Serve the chicken with the pancetta and garlic sprinkled on top. Drizzle the garlicky flavoured oil from the pan over the chicken and serve immediately.