In a large bowl, combine the flour, brown sugar, 1/4 teaspoon of the nutmeg and cinnamon. Cut in 1/2 cup butter until mixture resembles coarse crumbs; stir in nuts. Set aside.
Drain pears, reserving 1 cup juice. In a large saucepan, combine the sugar, cornstarch, salt, remaining nutmeg and reserved juice until smooth. Bring to a boil; cook and stir for 2 minutes or until thickened. Remove from the heat; stir in the lemon juice, zest and remaining butter.
Cut pears in half; arrange in pastry shell. Pour sauce over pears; sprinkle with reserved nut topping. Bake at 375° for 50-55 minutes or until golden brown.