Wash all grapes thoroughly under cold running water.
Pat the grapes dry using a clean kitchen towel.
Cut the grapes in half and place them in a large mixing bowl.
Add chopped walnuts to the bowl with the grapes.
In a separate bowl, mix Greek yogurt, honey, vanilla extract, and salt until smooth.
Pour the yogurt dressing over the grapes and walnuts.
Gently fold the mixture to ensure all ingredients are coated.
Transfer the salad to a serving dish or individual bowls.
Garnish with fresh mint leaves for a pop of color and flavor.
Serve immediately or chill for 30 minutes before serving.