Combine chicken, celery, onion, and parsley in a large Dutch oven; add water to cover. Cook, covered, 2 hours or until chicken is tender. Remove chicken from broth; cool. Remove meat from bones, and chop into bite-size pieces; set aside. Strain broth, and discard vegetables. Refrigerate chicken broth until all fat has risen to the top; skim off 6 tablespoons fat, and set aside. Discard excess fat, reserving 2 cups broth.
Melt reserved fat in a heavy saucepan over low heat; add flour, stirring until smooth. Cook 1 minute, stirring constantly. Gradually add milk and reserved broth; cook over medium heat, stirring constantly, until thickened and bubbly. Stir in salt, pepper, and chopped chicken.
Roll two-thirds of pastry to 1/8- inch thickness on a lightly floured surface; fit into a 2- quart casserole. Spoon chicken mixture into pastry shell.
Roll out remaining pastry to 1/8-inch thickness; carefully place over chicken mixture, leaving a 1-inch overhang at edge of casserole dish. Turn pastry edges under; press firmly to rim of casserole to seal and flute. Cut slits in top. Bake at 425° for 40 minutes or until golden brown. If pastry gets too brown, cover lightly with aluminum foil.
Oxmoor House Homestyle Recipes