
Wash and dry grapes and place in large bowl. Set aside.
In medium bowl, mix together cream cheese, sour cream, sugar, and vanilla, stirring until completely smooth.
Add sweet dressing mixture to grapes. Stir until evenly coated. Cover bowl and place in refrigerator at least 30 minutes, until ready to serve.
Immediately before serving, stir in ¼ cup chopped pecans, mixing until fully incorporated. Top grape salad with remaining ¼ cup pecans and sprinkle on brown sugar to garnish. Serve immediately after garnishing.