Smothered Chicken

Name: Smothered Chicken
Ingredients: All-purpose flour, for dredging; Three 1/2-pound chicken breast halves on the bone, halved crosswise; 3 whole chicken legs, cut into drumsticks and thighs; 4 tablespoons unsalted butter; 1 tablespoon vegetable oil; Salt and freshly ground pepper; 3 large onions (2 pounds), thinly sliced (see Note); 1/2 pound white mushrooms, stems trimmed, thickly sliced; 1 garlic clove, minced; 1/2 cup chicken stock or canned low-sodium broth; 1 bay leaf; 2 tablespoons chopped parsley