Creating Classic Hungarian Chicken Paprikash with Creamy Sauce is straightforward if you follow these steps:

1. Heat Oil: In a large skillet, heat the vegetable oil over medium-high heat.
2. Brown Chicken: Season the chicken thighs with salt and pepper. Place them skin-side down in the skillet and brown for about 5-7 minutes on each side. Remove the chicken from the skillet and set aside.
3. Sauté Onions: In the same skillet, add the chopped onion. Sauté until translucent, about 5 minutes.
4. Add Garlic: Stir in the minced garlic and cook for an additional minute until fragrant.
5. Incorporate Paprika: Lower the heat and add the sweet Hungarian paprika and cayenne pepper (if using). Stir well to coat the onions and garlic.
6. Add Chicken Broth: Pour in the chicken broth, scraping the bottom of the skillet to release any browned bits. Bring to a simmer.
7. Return Chicken: Place the browned chicken back into the skillet, skin-side up. Cover and simmer for 30 minutes, or until the chicken is cooked through.
8. Prepare the Creamy Sauce: In a small bowl, whisk together the sour cream and flour until smooth. Gradually add a few spoonfuls of the hot broth to the sour cream mixture to temper it.
9. Combine Sauces: Stir the tempered sour cream mixture back into the skillet, mixing well to combine. Heat through, but do not boil.
10. Serve: Taste and adjust seasoning if necessary. Garnish with fresh parsley before serving.

These steps will guide you to create a mouthwatering Classic Hungarian Chicken Paprikash that will have everyone asking for seconds!