Chicken New Hampshire

4 (6 ounce) boneless, skinless chicken breasts
Flour, as needed
Salt and pepper to taste
1 teaspoon vegetable oil
1 teaspoon butter
4 ounces julienned ham
1 red Delicious apples, cored, seeded and sliced thin
4 ounces sliced mushrooms
1/2 cup sliced onions
1/2 cup sherry
1/2 cup chicken stock
1/2 cup cream
1/2 cup chopped walnuts
1/2 teaspoon sage
1/2 teaspoon marjoram

Heat large saut