Whisk together balsamic vinegar, mustard, and olive oil. Add rosemary, oregano, and parsley.

Mince garlic and finely chop the onion.

Add to the vinegar mixture. Season well with salt and pepper.

Add the chicken to a plastic bag. Pour the mixture over. I add a few sprigs of rosemary for good measure.

Let marinate in the fridge for an hour or longer. Or if you are short on time, just for a couple of minutes while the oven preheats.

Preheat the oven to 400°. Pour the chicken into a baking dish.

Bake, uncovered for 20 minutes. Or until they are cooked through. Sometimes if I am feeling fancy, I'll broil them for the last few minutes to get the tops a little darker. Let sit for a few minutes before you serve. Spoon some of the sauce over the chicken.