INSTRUCTIONS:
Preheat oven to 325 degrees. Butter and flour a 10-inch tube pan. Set aside.
Sift together the flour, lemon pudding mix, salt and baking soda. Set aside.
Cream together butter, sugar and vanilla. Beat for 2 to 3 minutes, or until light and pale yellow in color. Add the eggs, one at a time, beating well after each addition, stopping and scraping the sides of the bowl as needed.
Reduce the speed of the mixer and add the sifted dry ingredients alternately with the sour cream. Mix until fully combined. Stir in the fresh lemon zest by hand.
Pour into prepared pan and place in the oven.
Bake, placing a piece of aluminum foil on top to prevent over browning, if needed, for 1 hour 20 minutes to 1 hour 30 minutes, or until a toothpick inserted into the center comes back clean.
Remove from oven and let cool in pan on a cooling rack for 15 minutes, then remove from the pan and let cool completely.
To make the glaze: In a medium-size mixing bowl, mix together the powdered sugar, lemon juice and butter. Drizzle over cooled cake