Chicken Pot Pie

3 cups cooked chicken or turkey, cubed
2 cups frozen mixed vegetables — thawed (Optional)
1 can cream of celery soup
1/4 cup chopped onion
2 tablespoons flour
2 cups chicken broth
1/4 teaspoon dried rosemary — crushed
1/4 teaspoon pepper

Topping:
1 cup self-rising flour (or 1 1/2 tsp baking powder plus 1/2 tsp. salt in bottom of a 1 cup measure, then add enough flour to make 1 cup)
1/4 teaspoon pepper
1 cup buttermilk
1/2 cup melted margarine — or less

…..
Combine chicken, vegetables, soup, onion and flour. Mix well. Stir in broth, rosemary and pepper. Boil over medium heat 1 minute, stirring occasionally. Pour into ungreased shallow 2 1/2 quart baking dish. For Topping: Combine flour and pepper. Stir in buttermilk and margarine just until moistened. Spoon over chicken mixture. Bake at 425 degrees for 25 minutes, until golden brown.