Most dry-cured hams need to be soaked in water before cooking. Rinse the ham; soak in several changes of water for about 10 minutes. If using prosciutto, there is no need to soak it. Drain and pat dry; finely dice to make 1 cup.
Heat 1 TBS of olive oil in large casserole. Stir in the onions, ham, garlic, and bay leaf. Cover and cook over low heat, stirring occasionally, until cooked down and very wet, about 1 1/4 hours. Uncover and remove from heat.
When the onions have simmered for an hour, begin to prepare the chicken. Working in batches, season the chicken pieces and lightly dust with flour, tapping off excess. Place a large skillet over medium-high heat; add 1 TBS oil, and when almost smoking add half the chicken, skin side down. Cook over medium-high heat until crusty and deep golden brown. Turn and brown other side, about 10 minutes total. Place chicken pieces on top of onions in the casserole. Repeat with remaining chicken.
Pour off fat from skillet; add brandy and wine, and carefully ignite while the mixture is warm. When the flames subside, add 1/2 cup water and bring to a boil. Add tomatoes and cook down until glazed, about 5 minutes. Stir in cream and pour over chicken
Cover the casserole and simmer over moderately low heat until the chicken is cooked through, about 20 minutes for breasts and 30 minutes for thighs and drumsticks; transfer chicken pieces to a deep platter as they are done, and keep under foil tent. If necessary, boil the sauce over high heat to reduce to 2 cups. Correct seasoning; pour sauce over chicken, and garnish with parsley. 6 servings.