Remove the grapes from the vine, wash thoroughly, and allow them to dry completely.
In a mixing bowl, combine the cream cheese, sour cream, sugar, and vanilla.
Using an electric mixer, beat until smooth and well blended.
Gently fold in the grapes, ensuring they are evenly coated in the mixture.
Just before serving, sprinkle with pecans and brown sugar, or stir them in if preferred.
Serve immediately or refrigerate until ready to enjoy.