Cut each chicken breast in half down the center. Cut off and discard any
membranes. Sprinkle with salt and pepper. Peel the onions and place them
in a saucepan with cold water to cover and salt to taste. Bring to a boil
and cook for about 2 minutes. Drain. Heat the oil in a large heavy skillet
and add the breast pieces. Cook for about 30 seconds and add the onions.
Cook for 10 minutes, then turn the chicken pieces. Scatter the mushrooms
over all and cook for 3 minutes more. Add the basil leaves, wine, and
butter. Cook, covered, about 3 minutes. Remove the basil leaves and
garnish each breast piece with one of the leaves. Serve with the onion and
mushroom sauce spooned over.

Makes 4 servings.