01 - Pat chicken thighs dry using paper towels. Generously season with salt, black pepper, smoked paprika, and dried thyme on all sides.
02 - Heat olive oil and unsalted butter in a large skillet or Dutch oven over medium-high heat. Place chicken thighs, skin-side down, and cook until golden brown, approximately 6 minutes per side. Remove the chicken from the pan and set aside.
03 - In the same pan, add sliced yellow onions. Cook, stirring occasionally, until onions are soft and golden, about 8 minutes. Add minced garlic and cook for an additional minute until fragrant.
04 - Evenly sprinkle flour over the onions. Stir well and cook for 1 to 2 minutes, ensuring removal of raw flour taste.
05 - Gradually pour in chicken broth while whisking to prevent lumps. Bring mixture to a gentle simmer, forming a smooth onion gravy.
06 - Return seared chicken thighs to the skillet, placing them skin-side up. Spoon some gravy and onions over each piece.
07 - Cover the skillet and simmer on low heat for 25 to 30 minutes, or until chicken is fully cooked through and gravy has thickened.
08 - Taste the gravy and adjust salt and pepper as needed before serving.
09 - Serve chicken thighs topped with the rich onion gravy. Garnish with chopped fresh parsley if desired.