Melt margarine in a 2 quart casserole dish. Mix baking powder, 1/4 c. Sugar, flour, and milk together. Pour over margarine. Mix cornstarch, nutmeg, vanilla, cinnamon, sugar, and peaches in a saucepan. Bring to a boil. Pour over ingredients in casserole. Bake at 350 degrees for 45 minutes to 1 hour.