This dish is easy and delicious, especially if you are a fan of the traditional french onion soup. All you need is a little time, as the onions need a patient hand to braise and caramelize to the deep brown and richly flavoured stage that forms the base of this dish.
I find a glass of wine makes me all the more patient.
serves 4 to 6
3 tablespoons unsalted butter
850 g onions, sliced into thin half-circles
Salt and freshly ground black pepper
4 garlic cloves, finely sliced
5 small sprigs thyme, leaves only
2 or 3 sprigs rosemary
2 cups chicken stock, divided
1 tablespoon balsamic vinegar
2 tablespoons Dijon mustard
1kg chicken pieces (thighs and drumsticks)
1 cup Gruyère cheese, finely grated or shaved
Melt the butter in a deep sauce pan with a lid over medium heat. When the butter has melted completely and starts foaming, add the onions and garlic. They will fill the pan to the top. Stir the onions to coat them in the butter. Season with salt and black pepper. Sweat the onions with a lid on 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, thyme leaves, and whole rosemary sprig, and cook for a few minutes more, stirring frequently. Turn the heat up to high and cook for a further 5 minutes, stirring all the time. You want them to develop a rich brown color. When the onions get quite dark, add 1 cup of stock. Add it slowly, stirring and scraping the pan vigorously to incorporate any burnt or stuck-on bits. When all of the liquid has been added, bring it back up to a simmer and simmer lightly for 5 minutes, or until the liquid has reduced somewhat.
Pre-heat your oven to 170°C.
Take the onions off the heat and pour them into an oven-safe dish with a lid. If you don’t have a dish with a lid, cover with a double layer of tin foil.
While the onions are cooking, brown the chicken. Heat another cast iron skillet or pan over medium-high heat. Pat the chicken thighs dry and season lightly with salt and black pepper. When the pan is hot, brown the chicken pieces for about 3 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 other cup of stock to the pan and stir vigorously, scraping up any browned bits on the bottom of the pan. Whisk in the balsamic vinegar and Dijon mustard. Simmer for 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 plenty of liquid in the baking dish.
Bake at 170°C for 30 minutes. Remove the chicken from the oven and turn the heat up to grill. Take the lid off the baking dish, and sprinkle the cheese evenly over the top of the chicken pieces. When the grill has heated up, return the dish to the oven and grill until the cheese is melted and golden (about 3-4 minutes depending on your grill).
Serve with some roasted veggies and potatoes, or a crispy salad.