1. With a fork, prick bottom and sides of unbaked pastry in pan at about 1 inch intervals. Bake in a 375 degree regular or convection oven until golden, 15 to 20 minutes; let cool on a rack.
2. Meanwhile, in a bowl, mix cream cheese and 1/2 cup sugar until smooth. Spread evenly over bottom of cool pastry.
3. In a blender or food processor, whirl 1 cup sliced peaches, remaining 3/4 cup sugar, orange juice, and constarch until smooth. Pour into a 3 to 4 quart pan; stir over medium heatuntil mixture boils and thickens, about 4 minutes. Remove from heat and stir in lemon juice.
4. Add remaining 5 1/2 cups peaches to hot peach glaze and miz to coat slices. Let cool until tepid, about 25 minutes, then scrape onto cream cheese mixture in crust.
5. Chill, uncovered, until firm enough to cut, at least 3 hours.
Cut into wedges and serve.