Spread 1/2 the apples in the pastry shell.Combine next 6 ingredients.Spread 1/2 the mixture over the apples.Spread in remaining apples atop first layer.Top with remaining remaining crumbs and walnuts.Bake in a moderate oven 375 degrees F, about 50 minutes, covering with foil the last 25 minutes.Remove from oven. Pour syrup, evenly, over the pie.