1 refrigerated pie crust dough
3-4 slightly firm but ripe green D’Anjou pears, peeled, cut into thin slices, lengthwise
¼ cup granulated sugar
2 tablespoons flour or cornstarch
1 teaspoon ground cinnamon
¼ teaspoon ground ginger
¼ teaspoon salt
1 tablespoon lemon juice
½ teaspoon lemon zest
½ tablespoon butter, cold and cut into 4 pieces
1 egg, beaten
coarse turbinado sugar or granulated sugar, for sprinkling