Preheat oven to 375°F (190°C)
In a large bowl, mix flour and salt. Add cold butter, and cut in with a pastry blender until crumbly
Gradually add cold water to form a dough; knead gently 2-3 times
Split dough in half, shape into disks. Chill 30 minutes
Roll out one disk into a 12-inch circle. Transfer to a 9-inch pie dish and trim edges
In a separate bowl, combine peaches, blueberries, sugar, cornstarch, lemon zest, juice, cinnamon, and nutmeg
Pour filling into prepared crust
Dot the surface with small butter pieces
Roll out second dough disk for top crust. Cut into strips for lattice or drape whole
Brush top crust with milk (or halal-approved alternative) and sprinkle butterscotch chips if desired
Bake 45-50 minutes, until golden and bubbly. Cool before slicing