2. Cut 4 round pieces of parchment paper large enough to contain the chicken and vegetables when folded in half.
4. Spray the parchment rounds with non-stick cooking spray.
5. Place a chicken breast in the center of each piece of parchment. Divide the onions, tomatoes, olives, herbs and cheese equally and lay them on top of each chicken breast. Drizzle with olive oil and season with salt and pepper.
6. Fold the paper in half and crimp the edges leaving one end uncrimped. Pour a little wine through the opening in each pouch, distributing it evenly. Crimp and seal the open end.
7. Place the envelopes (papillotes) on sheet pans and bake in the preheated oven for 30 to 40 minutes, until the chicken is cooked through.
8. Place a parchment pouch on each plate and slice open the top with a sharp knife or scissors.
NOTE: If you can't find parchment paper, you can substitute aluminum foil bags.