Cream shortening and sugar.
Add eggs one at a time, beating after each addition.
Sift together flour, baking soda, baking powder and salt.
Add alternately with buttermilk to creamed mixture.
Add 2 1/2 tablespoons lemon juice and beat with mixer for 2 minutes.
Bake in tube pan for 1 hour at 300 degrees.
Add glaze of 2 1/2 tablespoons of lemon juice and enough powdered sugar to spread easily.