01 - Pat chicken thighs dry with paper towels and season liberally with salt, black pepper, smoked paprika, and dried thyme.
02 - Melt olive oil and unsalted butter together in a large skillet or Dutch oven over medium-high heat.
03 - Arrange chicken thighs, skin-side down, in the hot pan. Sear until skin turns golden brown, about 6 minutes per side. Transfer chicken to a plate.
04 - Add sliced onions to the same pan. Cook, stirring occasionally, until softened and golden, approximately 8 minutes. Stir in minced garlic and cook until fragrant, about 1 minute.
05 - Sprinkle flour evenly over onions. Stir to combine and cook for 1 to 2 minutes to remove the raw flour taste.
06 - Gradually pour in chicken broth while whisking to dissolve any lumps. Bring the mixture to a gentle simmer.
07 - Return chicken thighs to the pan, skin-side up. Spoon gravy and onions over the chicken. Cover and simmer on low heat for 25 to 30 minutes, until chicken is fully cooked and the gravy thickens.
08 - Taste the gravy and adjust salt and pepper as needed.
09 - Serve chicken topped with the rich onion gravy, garnished with fresh parsley if desired.