Preheat oven to 350°.
Coat bottom and sides of an 8-inch loaf pan with cooking spray; dust with 1 tablespoon flour, discarding any excess flour. Set aside.
Spoon 1 3/4 cups flour into dry measuring cups; level with a knife. Stir together flour, baking powder, baking soda, and salt.
Beat butter, sugar, lemon rind, vanilla, egg, and egg whites with a mixer at medium speed until smooth. Add flour mixture, alternately with yogurt and beginning and ending with flour mixture; beat well after each addition. Pour into prepared pan, spreading evenly.
Bake at 350° for 55 to 60 minutes or until a wooden pick inserted in center comes out clean. Place cake on wire rack.
Stir together 3 tablespoons sugar and lemon juice. Spoon mixture over hot cake. Cool 20 minutes. Remove from pan. Cool completely on wire rack.