01 - Whisk together flour, salt, and sugar in a large bowl until thoroughly combined.
02 - Cut cold butter into flour mixture using a pastry cutter or fingertips until mixture resembles coarse crumbs with some pea-sized pieces remaining.
03 - Gradually add ice water, mixing gently just until dough comes together. Divide in half and form into two discs. Wrap and refrigerate for at least 1 hour.
04 - Roll one dough disc on lightly floured surface to fit 9-inch pie plate. Press gently into plate, trim edges, and refrigerate while preparing braid strips.
05 - Roll second disc to 1/4-inch thickness. Cut twelve long, even strips approximately 1/2 inch wide.
06 - Group strips into three sets of four. Pinch tops together. Braid by crossing left-most strip over, under, over remaining strips. Repeat with new left-most strip until fully braided.
07 - Carefully transfer braids to chilled pie edge. Press gently to adhere and trim excess. Use small amount of water to seal edges if necessary.
08 - Refrigerate pie for 15 minutes to firm crust. Preheat oven to 400°F.
09 - Whisk egg with milk and brush evenly over braided crust. For blind baking, line with parchment and fill with pie weights.
10 - Bake for 12-15 minutes until golden brown. Remove weights and continue baking if fully crisp crust is desired. Fill and complete baking according to your pie recipe.