Preparation Preheat oven to 325°F. Butter and lightly flour 2 heavy large baking sheets. Sift flour, cornmeal and salt into large bowl. Beat butter and sugar in another large bowl until creamy. Beat in 3 yolks, 1 at a time, until well blended. Beat in dry ingredients in 3 additions. Mix in water and grated lemon peel and beat until smooth dough forms. Turn dough out onto generously floured surface and knead until smooth, about 8 turns. Roll out dough to 6x8-inch rectangle about 1 inch thick. Cut rectangle into 1-inch diamond shapes. Transfer cookies to prepared baking sheets, spacing 2 inches apart. Beat remaining yolk in small bowl. Brush cookies with yolk. Bake until cookies are light golden, about 30 minutes. Transfer to racks; cool. (Can be prepared 3 days ahead. Store in airtight container.)
Preparation Preheat oven to 325°F. Butter and lightly flour 2 heavy large baking sheets. Sift flour, cornmeal and salt into large bowl. Beat butter and sugar in another large bowl until creamy. Beat in 3 yolks, 1 at a time, until well blended. Beat in dry ingredients in 3 additions. Mix in water and grated lemon peel and beat until smooth dough forms. Turn dough out onto generously floured surface and knead until smooth, about 8 turns. Roll out dough to 6x8-inch rectangle about 1 inch thick. Cut rectangle into 1-inch diamond shapes. Transfer cookies to prepared baking sheets, spacing 2 inches apart. Beat remaining yolk in small bowl. Brush cookies with yolk. Bake until cookies are light golden, about 30 minutes. Transfer to racks; cool. (Can be prepared 3 days ahead. Store in airtight container.)