This recipe came to me from Caryn Relkin. Really delicious. Really easy. All done on the stove top in one skillet.

Ingredients

1/3 cup olive oil - divided
2 cups sliced onions
2 t balsamic vinegar
Garlic salt
2 lbs boneless skinless chicken breasts - I do buy the thin cut chicken breast for this.
2 cups beef, or chicken or vegetable broth
1/2 t dried sage
1/2 r dried thyme
2 T flour
Swiss cheese

Directions

Heat 2 T olive oil in skillet. Add onions and season with garlic salt. Cook, stirring occasionally for about 15 minutes. Onions will soften and caramelize.
Add balsamic vinegar and cook another 3 minutes - until onions are darkened but not burned.
Remove onions from skillet.
Heat remaining olive oil on medium high. Add chicken and sear on both sides until golden brown - about 2 minutes each side. Remove chicken from skillet.
Add the sage and thyme to the broth.
Pour broth into skillet and bring to a boil, scraping up bits from pan bottom.
Mix flour in a small bowl with a small amount of water to get rid of lumps. Now whisk flour into sauce and cook on medium for 5 minutes - until thickened.
Add back the onions and the chicken. Cook on low for about 8 to 10 minutes so the chicken cooks through. Add Swiss cheese and heat until cheese is gooey and melty.