Per serving

1 boneless skinless chicken breast half or cutlet*
Salt and pepper
1-2 tablespoons basil pesto**
1-2 cherry tomatoes or 1 small Campari or plum tomato, sliced (optional)
2 tablespoons shredded mozzarella cheese (or more to taste)

Instructions

Preheat the oven to 400 degrees F, and lightly grease a baking dish big enough to fit the desired number of servings without overlapping.
Place the chicken in the baking dish, lightly sprinkle both sides with salt and pepper, and then evenly spread the pesto over the top of each chicken breast. (I use about 1 tablespoon per breast, a bit more if it’s large. I typically spread the pesto on the top of the chicken only, but for more pesto flavor, you may spread some over the bottom of the breast, too.)
For boneless, skinless chicken breasts, bake for 17-20 minutes or until chicken is just about cooked through the center. Remove from the oven, top with tomatoes and cheese, and then bake for an additional 3-4 minutes or until cheese is melted and the chicken is just cooked through. For chicken cutlets, bake for 10-12 minutes, and then continue as directed for regular boneless, skinless breasts. With either, check a few minutes early and add a few minutes as needed to account for oven and varying size chicken breasts.

Notes

*When the chicken breasts are large, I sometimes cut them in half horizontally (as though you were going to open the piece like a book, only cutting the whole way through) to make two thinner cutlets. This is also a great way to stretch the number of servings from a single package of 3-4 chicken breasts.
**I like to use a thicker pesto for this recipe as opposed to one that has been thinned heavily with olive oil, but use what you enjoy. Whichever pesto is used, the olive oil will cook out of it while baking and mix with the natural juices from the chicken. This may be drizzled over pasta, rice, or another grain of choice for serving, if desired.
Kitchen Tip:
The pictured baking dish contains three boneless, skinless chicken breast halves that weighed a total of 1 1/2 pounds. When I purchased the package of chicken, I thought there were four pieces in it. Cutting each breast into two thinner cutlets allowed me to stretch the meal yet nobody felt as though he was getting shortchanged with a mere half-piece of chicken, as would have been the case if I had cut them in half the traditional way. Since chicken breasts are often quite large (these weighed a generous half-pound each) this method also offers a way to better control portion size. As an added benefit, the thinner breasts will cook in roughly half the time.
I’ve also come to prefer the tenderness of the cutlet option, and the higher pesto-to-chicken ratio ratchets up the flavor. However, if you’d like to skip the cutting step or simply prefer a heartier serving of chicken, feel free to use the standard option.