I seasoned two chicken breasts with salt, pepper and Italian seasoning and grilled them just until they they were slightly pink. Since I planned to finish cooking the chicken in the oven with the sauce I didn't want them to be dry.
I sprayed a baking dish with oil, sliced each breast into three portions and spread Costco's pesto on top (we keep a jar of this in the fridge).
I sprinkled the top with grated Parmesan cheese. Covered with foil and baked for about 15 minutes at 350, uncovered the top and baked for about 5 minutes more.
We served it with a spinach salad and vegetables. Or you could serve it over spaghetti if you want it to be a more rustic dish. There are several variations you can add...cooked spinach as a layer between sauces, or cook the chicken on a bed of spaghetti squash.