3 cups sugar
enough pie dough for double crust pie
all-purpose flour, for work surface
1/8 teaspoon salt
7 large eggs, lightly beaten
1. Wash and cut 2 lemons crosswise into paper-thin slices. It is very important to slice the lemons as thin as possible; use a mandoline for best results. Remove seeds and transfer to a large bowl. Remove peel and pith of remaining lemon. Slice lemon flesh crosswise into very thin slices. Remove seeds and add to bowl with other lemon slices. Add sugar and toss well to coat. Cover bowl with plastic wrap, and let mixture stand overnight, stirring occasionally.
2. Preheat oven to 450 degrees. Roll 1 piece of dough into a 13-inch round and fit dough into a 10-inch pie plate, pressing it into the edges; refrigerate 15 minutes.
3. Add salt and whole eggs to lemon mixture; stir until well combined. Pour into chilled pie crust.
4. Roll remaining piece of dough into a 13-inch round, cut some slashes into dough and place over filling and crimp edges to seal. Brush top of crust with egg whites.
5. Transfer pie to oven and bake 15 minutes. Reduce oven temperature to 375 degrees and continue until crust is golden brown and shiny, about 30 minutes.
Source: Martha Stewart