In A Saucepan, Saute Onion In Butter Until Tender. Add The Soup, Turkey, Apple, Raisins, Lemon Juice And Nutmeg; Mix Well. Spoon Into An Ungreased 11-In. X 7-In. X 2-In. Baking Dish. On A Floured Surface, Roll Pastry To Fit Top Of Dish. Cut Vents In Pastry, Using A Small Apple Cookie Cutter If Desired. Place Over Filling; Flute Edges. Bake At 425 Degrees F For 25-30 Minutes Or Until Crust Is Golden Brown And Filling Is Bubbly.