Chicken with Peppers and Balsamic Vinegar

Chicken with Peppers and Balsamic Vinegar 
adapted from the Italian American Cookbook

6 tbl extra-virgin olive oil
1 large red bell pepper, cored and cut into 1 x ¼ inch stips
2 medium yellow onions, sliced
Salt, preferably kosher
Freshly ground black pepper
4 garlic cloves, minced
4 boneless, skinless chicken breast halves (1 ½ to 2 lbs total)
2 tbl dry white wine, such as soave (1 part white vinegar, 1 part water - so for this it would be 1 tbl of vinegar and 1 tbl of water).
6 tbl balsamic vinegar

In a large saute pan, heat 3 tbl of the olive oil over medium-high heat.  Add the bell pepper and onions, and cook, stirring several times, until softened and browned, about 10 minutes.  Season with salt and pepper to taste, add the garlic, and cook, stirring, for another 2 minutes. Transfer the vegetables to a bowl and set aside.

Season the chicken breasts with salt and pepper.  In the same saute pan over medium heat, heat the remaining 3 tbl olive oil.  When it is hot, add the chicken breasts and saute until browned on both sides and cooked through, 5 to 8 minutes. Check the chicken frequently as it is very easy to overcook these.

Add the vegetables to the chicken, and heat for 1 minute.  Add the wine, scraping up the brown bits on the bottom of the pan.  Adjust the seasonings.  Add the balsamic vinegar, stir with the chicken, and cook for 1 minute.  Serve immediately.