Brown chicken pieces in 1/3 cup dressing over low heat.
Add onions, tomatoes, seasonings, and 1/4 cup dressing to pan with chicken. Cover and simmer for 45 minutes.
Remove chicken and vegetables to serving platter. Reserve the drippings left in the pan.
To prepare the sauce, gradually add wine to flour in a small bowl, stirring until well-blended.
Gradually add wine-flour mixture to the hot drippings in the pan. Cook, stirring constantly until the mixture boils and thickens. Simmer 3 minutes, stirring constantly. Serve this sauce on the side with the chicken.