Heat the vegetable oil in a large skillet or Dutch oven over medium heat.
Season the chicken thighs with salt and pepper. Add them to the skillet, skin-side down, and brown for about 5-7 minutes on each side until golden. Remove the chicken from the skillet and set aside.
In the same skillet, add the chopped onion and sauté for about 5 minutes until translucent.
Stir in the minced garlic and cook for another minute until fragrant.
Sprinkle in the sweet paprika and cayenne pepper (if using). Stir quickly to combine, taking care not to burn the paprika.
Return the browned chicken to the skillet. Pour in the chicken broth, cover, and simmer for 25 minutes on low heat.
In a small bowl, mix the sour cream and flour until smooth. Take a few spoonfuls of the sauce from the skillet and mix it into the sour cream mixture to temper it.
Add the sour cream mixture back into the skillet, stirring well to combine. Cook for an additional 5 minutes, ensuring not to boil, so the sauce remains creamy.
Adjust seasoning with salt and pepper as needed.
Serve hot, garnished with fresh parsley, over egg noodles or dumplings.