This a one of our family standby's. Super fast and really good.
4 large or 6 small chicken breasts
1 cup prepared pesto
1/4 cup Dijon mustard
1-1 1/2 cups shredded mozzarella cheese
Preheat oven to 350 degrees. Coat a 9x13 inch pan with cooking spray. Trim chicken breasts and place in pan. In a bowl, mix pesto and mustard then spoon over chicken. Sprinkle with desired amount of cheese. Bake in oven until center of chicken reaches 160 degrees, about 20-25 minutes.
I made this tonight for dinner but forgot to snap a picture. For those of you not too familiar with pesto, it looks a little like green barf but don't let that turn you off to it. Note to Katie - I made this a few years ago when at home and Skyler hated it even though he was too kind to actually tell me so (I'm not sure he actually tried it, but he didn't eat it). Maybe he'll be less afraid now, maybe not.