Preheat oven to 450 degrees. Prepare pastry and line 9-inch pie plate. Line with double thickness of foil. Bake for 8 minutes, remove foil. Bake for 4 to 6 minutes more, or until lightly browned. Cool on rack. Reduce oven temperature to 425 degrees.
Separate egg yolks from whites; place whites in medium bowl and set aside.
In large bowl beat butter with electric mixer until fluffly. Beat in sugar until combined. Beat in egg yokes, lemon peel, lemon juice, flour, and salt until just combined. Add milk; beat until just combined (mixture will be thin and appear curdled).
Thoroughly wash beaters. In medium bowl, beat egg whites with mixer on medium speed until stiff peaks form (tips stand straight). Fold egg whites into beaten mixture. transfer mixture to prebaked crust.
Loosely tent top of pie with foil to prevent overbrowning, making sure the foil does not touch filling. Bake 10 minutes. Reduce heat to 350 degrees. Bake for 20 to 25 minutes more until set in the center.
Cool 1 hour on wire rack. Cover and refrigerate 3 hours. To serve top with Candied Lemon Slices.
Candied Lemon Slices: In a small saucepan, combine sugar, water; bring to boiling. Add thinly sliced lemon. Simmer gently, uncovered for 12 to 15 minutes or until syrupy. Transfer slsices to waxed paper. Discard remaining syrup.