To make crust, combine flour, butter, 1 egg, and salt in bowl and
work with fingers until mixture resembles coarse crumbs. Add enough
cold water to make soft dough. Wrap in waxed paper and chill
2 hours.
To make filling, combine cheeses, 2 eggs, watercress, nutmeg,
pepper, and sugar in mixer bowl and mix thoroughly.
Divide chilled crust in halves. Roll half of pastry almost
paper-thin and fit into 9" pie plate. Spread filling into shell.
Roll other half of pastry very thin and place over filling. Trim
and crimp edges. Brush with beaten egg white, if desired, and bake
at 325°F for 45 to 55 minutes, or until pastry is golden. Cut in
wedges to serve.
