Buttermilk Cake

1 c shortening
3 c sugar
1 T grated lemon rind
1 t salt
1 t vanilla
2 t lemon juice
6 eggs, separated
2 1/2 c plus 2 T flour, sifted
1/4 c plus 2 T cornstarch
1 c buttermilk
1/2 t baking soda
1 c butter
1 c sugar
1/4 c water
1 egg, beaten
1 T grated lemon rind
3 T lemon juice

Preheat oven to 350 degrees. Grease and flour a 10-inch tube pan; set aside.  In large mixer bowl, cream shortening, gradually adding 3 cups of sugar. Beat at medium speed on electric mixer until smooth, Add 1 tablespoon lemon rind, salt, vanilla, and 2 teaspoons lemon juice; beat on medium speed until blended. Add egg yolks and beat well. Set aside.

Combine flour and cornstarch; set aside. Combine buttermilk and soda; add to creamed mixture alternately with flour mixture. In medium mixing bowl, beat egg whites with electric mixer until stiff peaks form. Gently fold into batter.

Pour batter into prepared 10-inch tube pan and bake at 350 degrees for 1 hour and 15 minutes. Cool in pan for 10 minutes, then remove from pan and finish cooling on a wire rack.

Combine butter and remaining ingredients in a small saucepan. Cook over medium heat, stirring constantly, until mixture comes to a boil. Pour over warm cake.