Start by thoroughly washing both the red and green seedless grapes under cool running water. Pat them dry with a clean kitchen towel to ensure they are completely moisture-free.

In a medium-sized mixing bowl, add the softened cream cheese and beat using a hand mixer on medium speed until it is completely smooth and creamy. Gradually incorporate the plain Greek yogurt, granulated sugar, brown sugar, and pure vanilla extract into the cream cheese.

Gently fold the creamy mixture into the bowl of prepared grapes using a rubber spatula until evenly coated.

In a small bowl, mix half of the chopped pecans with the reserved brown sugar. Add half of this mixture to the grape salad, folding it in gently.

Cover the bowl with plastic wrap or a lid and refrigerate for at least 1 hour before serving. Sprinkle the reserved pecan topping over the salad just before serving.