Mash 2 cups sliced peaches; set aside.
Combine sugar and cornstarch in a heavy saucepan; stir well. Gradually add orange juice and mashed peaches. Cook over medium heat, stirring constantly, 8 minutes or until mixture thickens. Remove from heat; stir in lemon juice. Cool glaze completely.
Brush glaze over bottom and sides of baked pastry shell, coating well. Using remaining 4 cups peaches, place a layer of peaches in pastry shell. Brush with glaze. Repeat layers, ending with glaze, completely coating peaches. Refrigerate at least 3 hours.
Oxmoor House Homestyle Recipes