Massage each piece of chicken with pesto (leave a couple of spoonfuls for the mushrooms), and season with salt and pepper. Marinate the chicken in pesto for at least 1 hour.

Arrange on a baking sheet lined with aluminum foil or parchment paper. Bake in a preheated oven at 350 F for 30 minutes. Add in the mushrooms tossed in pesto and bake for another 10 minutes (mushrooms are optional). The chicken is ready when the kitchen thermometer inserted into the thickest part of the chicken registers an internal temperature of 165 F. I also like to add another coat of fresh pesto on top of the chicken breasts once they have baked. A thin layer is fine just to refresh the overall look.

Serve creamy pesto chicken on top of rice, cauliflower rice, zucchini noodles, more greens or roasted cherry tomatoes, and other favorite side dishes or grains.