Step 1

Adjust oven rack to lowest position and heat oven to 450 degrees. Pat chicken dry with paper towels and season with salt and pepper.

Step 2

Heat oil in 10-inch ovensafe skillet over medium-high heat until just smoking. Lay chicken skin side down in skillet and cook until well browned on first side, 6 to 8 minutes, reducing heat if pan begins to scorch. Flip chicken and continue to cook until lightly browned, about 3 minutes.

Step 3

Flip chicken skin side down and transfer skillet to oven. Roast until chicken registers 160 degrees, 15 to 18 minutes.

Step 4

Using potholders (skillet handle will be hot), remove skillet from oven. Transfer chicken to serving platter and tent loosely with aluminum foil.

Step 5

Being careful of hot skillet handle, pour off all but 1 tablespoon fat from skillet, add garlic, and cook over medium heat until softened, about 2 minutes. Stir in flour and cook for 1 minute. Whisk in broth, sherry, and thyme sprigs, scraping up any browned bits. Bring to simmer and cook until slightly thickened, about 5 minutes. Stir in any accumulated chicken juices and simmer for 30 seconds. Off heat, remove thyme sprigs and whisk in butter and lemon juice. Season with salt and pepper to taste. Pour sauce over chicken and serve.