In an ungreased heavy skillet, over medium heat, toast walnuts, stirring constantly, until golden, about 3 minutes.
They should have lost their raw taste.
Immediately transfer to a bowl to cool.
After about 5 minutes, coarsely chop walnuts.
Set aside.
In a blender mix cheese, Port and cream to a smooth paste.
Add grapes.
Pulse until grapes are chopped and distributed throughout mixture.
Scrape mixture into a serving bowl.
Stir in chopped nuts.
Cover tightly and refrigerate 30 minutes to overnight.
Serve cool or at room temperature, garnished with walnut halves and grapes.