Preparation Preheat oven to 350°F with rack in middle. Butter and flour an 8-by 2-inch round cake pan. Whisk together flour, baking powder, and salt. Stir together milk, zest, and vanilla. Beat together butter and granulated sugar with an electric mixer at medium speed until pale and fluffy, about 2 minutes. Add eggs 1 at a time, beating well after each addition. At low speed, mix in flour mixture in 3 batches, alternating with milk mixture, beginning and ending with flour mixture and mixing until each addition is just incorporated. Pour batter into cake pan and smooth top, then rap gently on counter to release any air bubbles. Bake until golden and a wooden pick inserted into center of cake comes out clean, 35 to 40 minutes. Cool in pan 10 minutes. Whisk together confectioners sugar and lemon juice until smooth. Turn out cake onto a rack set over a baking sheet, then reinvert. Brush top and side of cake with all of glaze. Cool completely. Cooks' note:Cake can be glazed 1 day ahead and kept at room temperature.
Preparation Preheat oven to 350°F with rack in middle. Butter and flour an 8-by 2-inch round cake pan. Whisk together flour, baking powder, and salt. Stir together milk, zest, and vanilla. Beat together butter and granulated sugar with an electric mixer at medium speed until pale and fluffy, about 2 minutes. Add eggs 1 at a time, beating well after each addition. At low speed, mix in flour mixture in 3 batches, alternating with milk mixture, beginning and ending with flour mixture and mixing until each addition is just incorporated. Pour batter into cake pan and smooth top, then rap gently on counter to release any air bubbles. Bake until golden and a wooden pick inserted into center of cake comes out clean, 35 to 40 minutes. Cool in pan 10 minutes. Whisk together confectioners sugar and lemon juice until smooth. Turn out cake onto a rack set over a baking sheet, then reinvert. Brush top and side of cake with all of glaze. Cool completely. Cooks' note:Cake can be glazed 1 day ahead and kept at room temperature.