|apologies for the poor quality photo; it doesn't do this delicious dinner justice!|
Braised French Onion Chicken with Gruyère
3 Tbsp unsalted butter
2 onions, sliced into thin half-moons
salt and freshly ground pepper
4 cloves garlic, minced
rosemary, to taste (I think I put a little too much in; 1-2 tsp should be enough)
2 cups chicken broth, divided
1 Tbsp balsamic vinegar
2 Tbsp Dijon mustard
3 lbs boneless skinless chicken breasts
2 ounces Gruyère cheese, finely grated (about 1 cup)
Melt the butter in a sauté pan over medium heat. When the butter has completely melted and foams up, add the onions. Stir as you add the onions to coat them in the butter. Sprinkle lightly with salt and black pepper. Cook the onions for about 40 minutes over low or medium heat, stirring occasionally.
When the onions have developed an evenly light beige color throughout, add the garlic and rosemary, and cook for a few minutes more, stirring frequently. Turn the heat up to high and cook for a further 5 minutes, stirring frequently. You want dark, slightly burnt spots to appear on the onions, and for them to develop a rich mahogany color. When the onions get quite dark, add 1 cup of the beef or chicken broth. Add it slowly, stirring and scraping up any burnt or stuck-on bits. When the liquid has been added, bring it back up to a simmer and simmer lightly for 5 minutes, or until it is somewhat reduced.
Take the onions off the heat and pour them into a 3-quart ove-safe dish with a lid (if you don't have one you can use a 9x13-inch baking dish covered with a double layer of foil).
While the onions are cooking, brown the chicken. Heat a 10-inch pan over medium-high heat. Pat the the chicken breasts dry and season lightly with salt and pepper. When the pan is hot, add the chicken and brown for about 5 minutes on each side. When they've developed a golden-brown crust, remove from the pan and set on top of the caramelized onions in the baking dish.
Add the remaining 1 cup of broth to the pan. Stir, scraping up any browned bits on the pan. Whisk in the balsamic vinegar and Dijon mustard. Simmer about 5 minutes, or until reduced by half. Pour this sauce over the chicken and onions, and put the lid on the baking dish. The chicken and onions will look quite saucy; there will be a good amount of liquid in the baking dish.
Bake at 325 degrees for 30 minutes. Remove from the oven and sprinkle the cheese evenly over the chicken. Return the dish to the oven and cook another 4-5 minutes, or until the cheese is melted.
Source: recipe slightly altered from the kitchn