How to Make It: Step-by-Step
For the best results, use a heavy-bottomed skillet (like cast iron or an oven-safe stainless steel pan) so you can seamlessly transition from the stovetop straight to the oven broiler.
Season 4 boneless, skinless chicken breasts with salt, pepper, and garlic powder. Melt 1 tablespoon of butter and 1 tablespoon of olive oil in your skillet over medium-high heat. Sear the chicken for 4–5 minutes per side until golden brown (it doesn't need to be cooked all the way through yet). Transfer chicken to a plate.
Turn the heat down to medium-low. Add another 2 tablespoons of butter to the same pan along with 3 large, thinly sliced yellow onions. Cook slowly, stirring occasionally. If the onions start to look dry or stick, add a splash of water. They are ready when they are soft, jammy, and a deep amber color.
Stir in 2 minced garlic cloves and 1 tablespoon of fresh thyme leaves, cooking for 1 minute. Sprinkle 1 tablespoon of flour over the onions and stir to coat. Pour in 1/2 cup of dry white wine (or extra broth) to deglaze the pan, scraping up all the savory brown bits from the bottom. Add 1 cup of high-quality beef broth and simmer until the sauce thickens slightly.
4- Braise, Cheese, and Broil
Nestle the chicken back into the skillet, spooning the onions and gravy over the top. Cover and simmer for 5 minutes until the chicken is cooked through (165°F). Turn your oven broiler to high. Top each chicken breast with a generous slice of Provolone or Swiss cheese, followed by a mountain of shredded Gruyère. Place the skillet under the broiler for 2–3 minutes until bubbling and golden brown.
What to Serve Alongside
Because this dish comes with its own built-in, rich onion gravy, you’ll definitely want something on the plate to catch all that extra sauce. It pairs beautifully over a bed of garlic mashed potatoes, buttered egg noodles, or alongside a crisp green salad and a warm, crusty baguette to mop up the skillet.
