Heat oven to 375F and spray the inside of an 8" x 11" baking dish with cooking spray.
If the breasts are uneven thickness, pound them (placed in a Ziploc bag and on a flat surface) to an even ¾"-1" thickness using a meat pounder. Sprinkle the breasts (both sides) with grated Parmesan cheese & freshly ground black pepper, and place them in the prepared baking dish.
Whisk together Caesar dressing and sour cream in a small bowl. Pour the Caesar/sour cream mixture over each breasts then sprinkle grated Parmesan cheese on top.
Place the prepared chicken in the oven and bake at 375F for 30 minutes or until a meat thermometer inserted in the thickest part of one of the middle breasts reads 150°F.
Turn the oven to broil and broil the breasts an additional 2-4 minutes or until the chicken turns golden brown. It can burn quickly, so watch it closely. When done, a meat thermometer should register 160F when stuck into the thickest part of one of the middle breasts. Remove from the oven, cover loosely with foil and allow chicken to rest 5-10 minutes before serving.