Blueberry-and-walnut Pie

-BLUEBERRY FILLING-
2 pt Blueberries
3/4 c Sugar
3 tb Cornstarch
3 tb Water
1 tb Grated lemon zest
3/4 c Walnut pieces
– toasted & coarsely chopped

WALNUT CRUMB TOPPING
4 tb Butter
1/4 c Sugar
1/2 ts Cinnamon
3/4 c Unbleached all-purpose flour
1/2 c Walnuts, coarsely chopped

MIXING THE PASTRY DOUGH: Stir together the dry ingredients in a bowl. Cut
up and add the butter; toss gently to coat. Rub in the butter until the
mixture looks sandy. Beat the egg and toss into the flour and butter
mixture. Press the dough together, wrap and chill it. FORMING THE PIE
SHELL: Lightly flour the work surface and dough. Roll the dough to a
14-inch diameter disk, 1/8-inch thick. Fit the dough into a 9-inch
oven-proof glass pie pan and trim away all but 1/4-inch of the excess
dough. Turn the excess dough under and flute the edge of the pie. Chill
while preparing the filling. MIXING THE FILLING: Rinse and pick over the
blueberries and drain them on a paper-towel-lined pan. Combine one third of
the berries and the sugar in a saucepan and bring to a simmer over medium
heat, stirring occasionally. Simmer the berries in the juices that
accumulate about 5 minutes. Strain the juices into another pan. Pour the
water into a small bowl and stir in the cornstarch to dissolve it. Return
the blueberry juices to a boil and beat about one quarter of it into the
dissolved cornstarch. Return the remaining juices to a boil and beat the
cornstarch mixture into it. Return the juices to a boil, beating
constantly, and allow to boil about 1 to 2 minutes, beating constantly.
Stir in the remaining blueberries, the cooked berries, lemon zest and
walnuts, and cool. MIXING THE CRUMB TOPPING: Cream the butter until soft,
add the sugar and cream until soft and light. Beat in the cinnamon. Mix in
the flour, then the walnuts. The mixture should fall into large, soft
crumbs. Pour the filling into the prepared pan and smooth. Scatter over the
crumbs and bake at 350F until the filling is set, the crumbs have colored
and the crust is baked through, about 40 minutes. Cool on a rack. Makes one
9-inch pie.