In a medium bowl, sift together the flour, sugar, & salt. Work in the shortening with a pastry blender until mixture resembles coarse crumbs. In a small bowl, whisk together egg & cold water; sprinkle over flour mixture and work with hands to form dough into a ball. Chill 30 min.
Preheat oven to 350. Roll out half the dough to 1/8 inch thickness. Place in a 9x13 baking dish; covering bottom and halfway up the sides. Bake for 20 min. or until golden brown.
In a large saucepan, mix the peaches, lemon juice, and orange juice. Add 1/2 c. butter and cook over med-low heat until butter is melted. Ina mixing bowl, stir together sugar, nutmeg, cinnamon, and cornstarch; mix into peach mixture. Remove from heat; and pour into baked crust.
Roll remaining dough to 1/4 inch; cut into 1/2inch wide strips. Weave strips into a lattice over peaches. Sprinkle with sugar and drizzle with melted butter.
Bake in preheated oven 35-40 min. or until top crust is golden brown.