Turn oven on to 350F. Spray the cooking spray onto the inside of a 8x11" baking dish.
If the breasts have an irregular thickness, pound them with a meat pounder to get 3/4 inch thickness.
Spread the grated Parmesan cheese and freshly ground black pepper on the breasts, then place them in the prepared baking dish.
In a small bowl, whisk together Caesar dressing and sour cream. Sprinkle the Caesar dressing or sour cream mix on each breast.
Bake the chicken for 30 minutes at 375F.
Broil the chicken breasts in the oven for 2-4 minutes.
A meat thermometer should register 165°F once it is done. It should be placed in the thickest part of the middle-breast. Cover the chicken with foil and allow it to rest in the oven for five to ten minutes before you serve.
Serve! If desired, garnish with chopped-parsley