Some people think baking is magical because of the science behind it. It is pretty cool, the way temperature and chemical reactions turn white powders into cakes and bread. But it’s almost as magical that you can use two whole lemons in this recipe, peels and all, and still come out with a cookie that’s sweet. That would be the magical power of two cups of sugar at work, taming one of the tartest things into almost complete submission. Almost.
Note: Begin the first step the day before you plan to bake these cookies.
2 lemons, washed and dried
2 cups plus 3/4 cup granulated sugar
2 1/4 sticks cold unsalted butter, cut into 1/2 inch pieces
1/2 teaspoon salt
3 cups all-purpose flour
4 large eggs, lightly beaten
Confectioners’ sugar, for sifting
Slice lemons as thinly as possible; remove seeds. Toss slices with 2 cups sugar; transfer mixture to a flat resealable plastic container. Place in the refrigerator overnight.
Place butter, salt, remaining 3/4 cup sugar, and flour in the bowl of a food processor. Process until mixture is crumbly and starts to hold together.
Heat oven to 400F degrees. Line a 12-by-17-inch baking pan with parchment paper. Press dough evenly into the bottom and up the sides of the pan, making sure there are no holes. There should be at least 1/2-inch crust of dough going up the sides of the pan. Bake until golden brown, about 20 minutes. Transfer to a wire rack to cool completely, about 15 minutes.
Place lemon-sugar mixture and eggs in the bowl of a food processor. Process until lemon rinds are in 1/4- to 1/2-inch pieces, 30 to 40 seconds. Pour mixture over cookie crust. Bake until set, 15 to 20 minutes. Cool on a wire rack. Trim 1/2 inch around edges of pan. Cut into about sixty 1 1/4-by-2-inch pieces. Sift confectioners’ sugar over cookies.