In a medium bowl, beat cream cheese and butter until smooth. Add lemon zest.

Begin adding powdered sugar, about one cup at a time. Beat well to incorporate each cup before adding more.

As frosting begins to thicken (usually after a couple cups of sugar) begin incorporating the lemon juice by adding a little juice in between each sugar addition.

Use all of the lemon juice and adjust the final amount of powdered sugar to achieve ideal spreading consistency.