1 T balsamic vinegar
5 garlic cloves, minced
1 c fresh basil
2 T olive oil, separated
1/4 c water
4 boneless, skinless chicken breasts
1/2 red onion, sliced
1 pkg cherry or grape tomatoes, halved
1 c sliced mushrooms (opt)
1. Place vinegar, garlic, basil, 1 tablespoon olive oil, and water in a blender and blend well. Set aside. (You can do this up to several hours early and let it steep.)
2. Preheat oven to 375*. Score the chicken breasts deeply a few times on one side.
3. Sear chicken in remaining tablespoon of oil, over medium-high heat, until light brown (the middle will still be pink), about 3-5 minutes each side.
4. Place chicken in a 9x9 pan, cut sides up, and cover with vinegar mixture, making sure to get it deep in the slits; sprinkle onions, tomatoes, and mushrooms on top.
5. Bake, uncovered, for about 40 minutes, until chicken is cooked through.