Preheat oven to 350 degrees. Grease 9 x 13 inch baking pan. Follow box directions for butter golden cake mix adding water, butter and eggs (as indicated on the package). Stir in lemon zest. Spoon in pan and bake for 30 minutes or until toothpick inserted in center comes on clean.
Meanwhile stir lemon pudding mix and milk according to box instructions. Cover and refrigerate.
Remove cake from the oven and immediately poke holes about every inch using the back of a wooden spoon. Spread the pudding over the cake gently pushing into the holes. Cool completely.
Beat cream cheese, butter, lemon juice, lemon zest and powdered sugar in 1/2 cup intervals until desired consistency.
Reserve 1 1/2 cups frosting if piping edges and centers. Spread remaining frosting over cake blending with remaining lemon pudding. Top with piped edges, centers and lemon slices if desired.
Refrigerate for several hours to overnight to fully set.
Notes
There will be some lemon pudding on the top. When spreading the frosting work them in together.
If you are not piping the frosting you can cut the amount of powdered sugar down a little.
Grease your baking pan well.
To poke holes in the baked cake use the top of a wooden spoon or the fat end of a thick pair of chopsticks.
Poke holes a little over one inch apart. If they are too close the cake will be too moist and difficult to cut. If they are too far apart there will not be enough lemon pudding throughout the cake.
When frosting the top the icing will be mixed in with any residual lemon pudding.
The cake looks very pretty with the edges and top piped with slices of lemon for garnish.