How to Make It
Preheat the oven to 400°. Cut the excess skin from the chicken legs and reserve. Arrange the chicken legs on a rimmed baking sheet, skin side up, and season with salt and pepper. Roast for about 25 minutes, until well browned.
Meanwhile, in a large enameled cast-iron casserole, heat the olive oil. Add the bacon, onion, garlic, serrano chile and the reserved chicken skin; season with a generous pinch each of salt and pepper. Cook over moderate heat, stirring occasionally, until the onion is just starting to brown, 10 to 12 minutes.
Add the potato, tomato paste, brown sugar, bay leaf and oregano to the casserole. Stir in the 1 tablespoon of paprika and cook over moderate heat for 7 minutes, stirring occasionally. Add the stock and bring to a simmer. Add the chicken legs and cook over moderately low heat until the chicken is white throughout, about 25 minutes.
Transfer the chicken to a platter and tent with foil. Remove and discard the bay leaf, then ladle the stock and vegetables into a blender or food processor. Add the 2 tablespoons of sour cream and the vinegar and puree until smooth; season the sauce with salt and pepper. Pour the sauce over the chicken and garnish with paprika, sour cream and dill. Serve with buttered egg noodles.