Ingredients:

• 3 tablespoons butter
• 2 pounds onions, sliced thinly
• 2 cloves garlic, minced
• 1 teaspoon dried thyme
• 2 tablespoons flour
• 2 cups chicken broth
• 1 tablespoon olive oil
• 1  1/2 pounds chicken thighs (boneless and skinless, if desired)
• salt and pepper to taste
• 2 tablespoon balsamic vinegar
• 2 tablespoons Dijon mustard
• 1 cup Swiss cheese, grated
• mashed potatoes, Italian bread or French bread, or noodles for serving, if desired

Directions:

1. Melt the butter in a large skillet over medium heat.  Add the onions and cook until a deep golden brown, about forty-five minutes, stirring occasionally. Add a bit of broth to deglaze the pan if needed.
2. Add the garlic, thyme and flour to the onions. Stir for one to two minutes to form a thick paste and cook off the flour taste.
3. Add one cup of broth.  Stir up all the pieces at the bottom of the pan and  bring onions to a boil, reduce the heat to medium low and simmer for 5 minutes.
4. While the onions are cooking heat the oil in another large skillet over medium-high heat.  Salt and pepper the chicken.
5. Add the chicken to the skillet with the oil and brown on both sides, about 8-10 minutes per side (for bone in chicken thighs) before setting aside.
6. Add the remaining cup of broth to the pan that held the chicken.  Scrape up all the browned pieces at the bottom of the pan.
7. Stir in the balsamic vinegar and mustard.  Bring mixture to a boil. Reduce the heat and simmer to reduce by half, about 10-12 minutes.
8. Place the onions in an oven safe pan, top with the chicken and broth from the chicken pan, cover with a lid or foil and bake in a preheated 350 degree oven for 20 minutes.
9. Sprinkle on the cheese and broil until it has melted and starts to brown, about 2-4 minutes.