Chicken with Vinegar Sauce

Step 1: In a large enameled cast iron casserole, melt the butter in the oil. Season the chicken with salt and pepper, add it to the casserole and cook over moderately high heat, turning once, until browned, about 10 minutes. Transfer the chicken to a plate. Add the chicken liver to the casserole and cook until browned, about 3 minutes. Finely chop the liver and reserve it for the sauce.

Step 2: Pour off all but 4 tablespoons of fat from the casserole. Add the garlic and shallots and cook over low heat, stirring occasionally, until translucent, about 2 minutes. Increase the heat to moderately high. Add the wine and vinegar and simmer until reduced by one-third, scraping up any browned bits from the pan, abut 4 minutes. Stir in the tomato paste, stock and 1/2 teaspoon of salt.

Step 3: Return the legs, thighs and wings to the casserole. Cover partially and simmer for 30 minutes, turning the pieces occasionally. Add the chicken breasts, cover partially and cook until all the pies are cooked through, about 15 minutes longer.

Step 4: Preheat the broiler. Transfer the chicken to a foil-lined baking sheet, skin side up. Using a paper towel, pat the chicken skin dry. Broil the chicken 3-inches from the heat for 2 minutes, or until the skin is browned and crisp.

Step 5: Boil the sauce until it has reduced to 1 1/2 cups, about 4 minutes. Add the reserved chicken liver and season with salt and pepper. Transfer the chicken to a platter, spoon the sauce on top and serve at once.