Preheat oven to 375 F degrees.
In a skillet fry the bacon and onion together until bacon is crisp and onion is transluscent. Set aside.
To butterfly the turkey breasts, cut the turkey breasts in half horizontally without slicing all the way through,and open it up like a book into one bigger piece. Place between 2 sheets of parchment paper or plastic wrap. With a meat mallet or rolling pin, gently pound the meat to make it as thin as possible. Season the breasts with salt and pepper.
Top the turkey breast with cheese, then the bacon mixture, leaving about an inch border, then roll it up and secure it with butcher's twine or kitchen string. Repeat with other breast.
Brown the turkey in a oven proof skillet with the olive oil, evenly on all sides. Place the skillet in the oven and roast the turkey breast for about 45 minutes.