Turkey Pot Pie or Turkey Shepherd's Pie

Turkey Pot Pie or Turkey Shepherd's Pie From The Culinary Institute of America adapted by Boston Globe with additions by YumSugar 3 tablespoons butter 1 medium onion, chopped 1 clove garlic, chopped 3 tablespoons flour 3 cups turkey or chicken broth, heated to boiling Salt and pepper, to taste 1 carrot, chopped 1 stalk celery, chopped 1 Yukon Gold or Yellow Finn potato, diced 4 cups diced cooked turkey 1 cup green peas (thawed if frozen - try not to use canned, they will be too mushy) 2 tablespoons chopped fresh parsley 2 nine-inch prepared pie crusts, frozen puff pastry sheets (thawed), or other topping such as leftover mashed potatoes Note: This recipe is for four individual pot pies, however I used the filling to make two larger sized pies: one shepherd and one regular. In a large saucepan, heat the butter over medium-high heat until it shimmers. Add the onion and cook, stirring often, for 10 minutes or until tender.