01 - Pat chicken thighs thoroughly dry using paper towels. Generously season both sides with salt, black pepper, smoked paprika, and dried thyme.
02 - Heat olive oil and unsalted butter in a large skillet or Dutch oven over medium-high heat. Arrange the chicken thighs skin-side down and sear until golden brown, approximately 6 minutes per side. Remove the chicken and set aside on a plate.
03 - In the same pan, add sliced onions. Cook, stirring occasionally, until softened and golden-brown, about 8 minutes. Stir in minced garlic and cook for 1 additional minute.
04 - Sprinkle flour evenly over the onions. Stir to combine and cook for 1 to 2 minutes, allowing the flour to absorb fat and eliminate the raw taste.
05 - Slowly pour in the chicken broth while whisking continuously to prevent lumps. Bring the mixture to a gentle simmer so the gravy thickens evenly.
06 - Nestle the seared chicken thighs, skin-side up, into the simmering gravy. Spoon some onions and gravy over each thigh.
07 - Cover with a tight-fitting lid and simmer on low heat for 25 to 30 minutes until the chicken is fully cooked through and the gravy has thickened.
08 - Remove the lid, taste the gravy, and adjust salt and pepper as needed to achieve desired flavor.
09 - Plate the chicken thighs and ladle generous amounts of onion gravy over each portion. Finish with chopped fresh parsley if desired.