Pat the chicken thighs dry with paper towels. Season both sides with kosher salt, black pepper, and smoked paprika.

Heat olive oil in a large skillet over medium-high heat. Add the chicken thighs skin-side down and cook for 6 to 8 minutes until deeply golden and crisp. Flip and cook 3 minutes more. Transfer to a plate.

Reduce the heat to medium. Spoon off excess fat if needed, leaving about 1 tablespoon in the skillet. Add the sliced onion and cook for 3 to 4 minutes until softened.

Stir in the minced garlic and cook for 30 seconds until fragrant.

Add the sliced apples and cook for 2 to 3 minutes, until just beginning to soften.

Pour in the apple cider and chicken broth. Stir in the Dijon mustard, apple cider vinegar, and thyme. Scrape up any browned bits from the bottom of the pan and bring the sauce to a gentle simmer.

Return the chicken thighs to the skillet skin-side up. Simmer over medium-low heat for 18 to 22 minutes, until the chicken is cooked through and reaches 165 degrees F in the thickest part.

Transfer the chicken to a clean plate. Stir the butter into the sauce and simmer for 2 to 4 minutes, until slightly thickened and glossy.

Serve the chicken with the apple cider sauce and softened apples spooned over the top. Garnish with extra thyme if desired.