Wash the grapes and dry thoroughly with a kitchen towel. Set aside.
Combine the gorgonzola and cream cheese in the bowl of a stand mixer fitted with the paddle attachment. Mix on high speed until completely homogenous, scraping down the sides as needed.
Grind the pistachios in a food processor, transfer to a bowl and set aside.
Coat the dry grapes completely in the cheese mixture and then roll in the crushed pistachios to coat evenly. Refrigerate for at least 2 hours in an airtight container before serving.