What you need:
* 1 cup fat-free sour cream
* 1 teaspoon grated lemon zest
* 2 tablespoons fresh-squeezed lemon juice
* 1/2 teaspoon granulated sugar
What you do:
In a medium bowl, combine sour cream, lemon zest, lemon juice, and sugar; mix until well blended.
Place in fridge to set for at least 30 minutes before serving.