Step 1

Preheat oven to 425F and set rack to top third position in oven.

Step 2

In a small bowl, whisk together salt, pepper, and paprika. In a separate bowl, combine beef stock, Worcestershire sauce and sherry. Set aside.

Step 3

Thoroughly pat chicken dry. Separate skin from thigh meat by inserting your index finger between the two and lifting up gently. Season both sides of chicken, as well as underneath the skin.

Step 4

Add oil to heavy oven-safe skillet and heat over medium-high. Once hot, add seasoned chicken, skin side down and sear for 5 to 6 minutes. Flip to the other side and continue cooking for 3 to 4 minutes. Remove from pan and set aside.

Step 5

Add butter to the pan and once foaming subsides, add onions, sugar and a couple generous pinches of salt. Reduce heat to medium and cook onions until translucent, 4 to 5 minutes, stirring occasionally. Add garlic and thyme, and cook for 1 minute.

Step 6

Pour in stock mixture. Place chicken on top of onions. Transfer to the oven and cook for about 25 minutes, until the onions are caramelized and saucy and a meat thermometer inserted into the thickest part of the chicken reaches 160 F. Top chicken with shredded Gruyère and parsley. Cook for 5 to 6 minutes until cheese is melted.

Step 7

Serve immediately with crusty bread.