Chicken with pesto/and balsamic vinegar

I found this recipe here I used boneless, skinless thighs instead of the breasts however.

 Ingredients:
 4 skinless, boneless chicken breasts (I used Thighs--8 of them )
 4 – 5 garlic cloves
 1 cup fresh basil
 1 tablespoon olive oil
 1 tsp. balsamic vinegar
 1/4 cup water
 1 cup sliced mushrooms (I used a medium sized jar of them)
 1 package of cherry or grape tomatoes
 1/2 red onion sliced (this was good so DO use the full amount)

 Preparation: Preheat oven at 375 degrees. Brown the chicken breasts in a pan. In a blender place the garlic, basil, olive oil, vinegar, water and pulse until pureed. Place the browned chicken breasts in a pyrex and cover with the basil, garlic mixture. Top with mushrooms, tomatoes and onion and bake for about 40 minutes or until chicken is fully cooked. Serve with brown rice and a salad. Or with mashed potatoes and Brussels --or whatever you desire.