1. Put rack in center of oven; heat oven to 350 degrees. Grease a 9-by-9-inch baking pan. Set aside.

2. For crust and topping, beat sugar, butter and salt in large bowl of electric mixer until creamy. Add flour. Mix until just combined.

3. Reserve about 1/2 cup mixture for topping; refrigerate until ready to use. Spoon remaining mixture into baking pan, distributing as evenly as possible. Put hand in small plastic food bag and press dough into a thin, even layer. Bake until lightly browned, about 15 minutes. Cool about 15 minutes.

4. Put egg white in small dish; stir with fork until frothy. Set aside.

5. For filling, combine flour, sugar and cinnamon in 1-quart bowl; add peach slices; toss to coat with flour mixture; the slices will be gooey. Closely overlap peach slices over slightly cooled crust. Use all peach slices (they cook down). Crumble reserved 1/2 cup topping evenly over peaches. Dab crumbs and surface with all of reserved egg white. Scatter pecans over top.

6. Bake until lightly browned, about 50 minutes. Cool completely on rack, then refrigerate until chilled. Cut into 2 1/4-inch squares. To do this more easily, cut into quarters and transfer each quarter to cutting board. Cut quarter into 4 squares. Serve chilled. These squares are best served the day that they are baked, but they can be made a day in advance. Refrigerate squares overnight on cookie sheet, arranged single layer, covered with foil.