01 - Pat chicken thighs dry thoroughly with paper towels. Season all sides generously with salt, black pepper, smoked paprika, and thyme.
02 - Heat olive oil and unsalted butter together in a large skillet or Dutch oven over medium-high heat. Arrange chicken thighs skin-side down and sear until the skin is deep golden and crisp, approximately 6 minutes per side. Remove chicken and set aside.
03 - Reduce heat to medium. In the same pan, add sliced onions. Cook, stirring occasionally, until onions are soft and golden, about 8 minutes. Add minced garlic and sauté for 1 minute until fragrant.
04 - Evenly sprinkle the flour over the cooked onions and stir constantly. Cook for 1 to 2 minutes to eliminate raw flour taste.
05 - Gradually pour chicken broth into the pan, whisking continuously to dissolve flour and prevent lumps. Bring to a gentle simmer, scraping up any browned bits from the bottom.
06 - Return the seared chicken thighs skin-side up to the skillet. Spoon gravy and onions over the chicken to coat evenly.
07 - Cover with a lid and simmer on low heat for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the gravy is thickened.
08 - Taste the gravy and adjust with additional salt and pepper as desired.
09 - Serve chicken thighs generously topped with onion gravy. Garnish with chopped parsley if desired. Pair with mashed potatoes, rice, or buttered noodles for a complete meal.