Preheat oven to 350 degrees.
Grease and flour fluted bundt pan and set aside.
In a large mixing bowl, combine cake mix, eggs, water, oil, lemon pudding mix, lemon zest and lemon juice, and beat with an electric mixer for about 2 minutes.
Pour into prepared pan and bake at 350 degrees until done (about 35-45 minutes).
Remove from oven and allow to cool for about 10 minutes.
Turn out onto serving plate and drizzle with lemon icing or dust with powdered sugar.
Open icing, remove and discard foil lid.
Microwave on high for about 20 seconds and stir well. (Microwave until icing reaches a pourable consistency.)
Stir in lemon zest and fresh lemon juice to taste, mix well.
Pour over cooled cake and serve.
Garnish with fresh lemon slices if desired.