Whip the cream in a medium bowl until stiff and season with salt and pepper. Set aside 1 ounce of the blue cheese, and mash the rest with a fork in a separate bowl. Stir in the basil, oregano and thyme, then fold in the whipped cream.
Place a 3 inch metal ring (or biscuit cutter) onto a serving plate, and fill the bottom with walnuts. Spoon the whipped cream mixture into the ring, and smooth the top. Carefully remove the ring. Sprinkle the remaining blue cheese and grapes over the top.