Spritz a 9x13 oven-safe dish or 9x13 foil tray with non-stick cooking spray.
Slice chicken in half horizontally through the thickness of the breast. Pound to ½ an inch thick. You can make this easier by placing chicken between sheets of plastic wrap or waxed paper when pounding.
Place the tray in the oven. Bake for 30 to 40 minutes (depending on the thickness of the chicken breast or until a meat thermometer reads 165°.