Line an 8-inch pie plate with half of the pastry. Roll out the rest
into a round large enough to cover the pie.
Boil the maple syrup and water together for 5 minutes. Thicken with
the cornstarch mixed with 2 tablespoons cold water. When creamy and
clear, add the chopped nuts and butter.
Pour into the pastry-lined pie plate and top with the second round
of pastry.
Bake in a preheated 450 degree F. oven for 30 minutes, or until the
crust is golden brown.