01 - Pat chicken thighs dry with paper towels and season generously on both sides with salt, black pepper, smoked paprika, and dried thyme.
02 - In a large skillet or Dutch oven, heat olive oil and unsalted butter over medium-high heat. Add chicken thighs skin-side down and sear until skin is golden brown and crisp, about 6 minutes per side. Transfer chicken to a plate.
03 - Add sliced onions to the same skillet and cook, stirring occasionally, until softened and golden, about 8 minutes. Stir in minced garlic and cook for an additional 1 minute until fragrant.
04 - Sprinkle all-purpose or gluten-free flour over the onions, stirring to coat. Cook for 1–2 minutes to remove any raw flour taste.
05 - Gradually pour in chicken broth while whisking constantly to prevent lumps. Bring mixture to a gentle simmer, allowing the gravy to slightly thicken.
06 - Arrange seared chicken thighs skin-side up in the gravy. Spoon onions and sauce over chicken pieces to coat.
07 - Cover the skillet and simmer on low heat for 25–30 minutes, until chicken is cooked through and gravy is rich and thickened.
08 - Taste the gravy and adjust as needed with additional salt or black pepper. Serve chicken topped generously with onion gravy and garnish with chopped fresh parsley if desired.