Step 1: In a large skillet, melt the butter over medium heat. Add the sliced onions and season them with a pinch of salt. Cook the onions for about 20-25 minutes, stirring occasionally, until they are golden brown and caramelized. Add the minced garlic, thyme, and oregano during the last few minutes of cooking for added flavor.
Step 2: While the onions are caramelizing, season the chicken thighs with the remaining salt and pepper. In a separate large skillet, heat the olive oil over medium-high heat. Once hot, add the chicken thighs and sear them for about 5-7 minutes on each side, or until golden brown.
Step 3: Once the chicken is seared, transfer it to the skillet with the caramelized onions. Pour in the dry Apple cider, using a wooden spoon to scrape up any brown bits from the bottom of the skillet.
Step 4: Add the beef broth to the skillet, reduce the heat to low medium, and let everything simmer for about 20 minutes.
Step 5: In the final minutes of cooking, sprinkle the mozzarella and Swiss cheeses generously over the chicken and onion mixture. Cover the skillet with a lid and let the cheese melt, about 5 minutes.
Step 6: Once the cheese is melted and bubbly, remove the skillet from the heat. Garnish with freshly chopped parsley and serve warm.
Equipment
Large Skillet
Wooden Spoon
Notes
For even more depth of flavor, consider using a mix of cheeses, such as Gruyère or provolone. Don’t rush the caramelizing process on the onions; patience is key for the best flavor.