Dice grilled Treviso, season to taste with salt and pepper, set aside. Heat oven to 375 degrees F. Fit pastry in 9-10 inch tart pan with removable bottom (or pie pan); bake for 17-22 minutes or until very lightly browned.
Meanwhile, in large mixer bowl combine cream cheese and blue cheese, beat until creamy, add cream, egg and pepper and beat until blended. Spread half of filling into baked pastry shell. Spread the chopped treviso over filling. Spread the rest of filling over treviso. Sprinkle bacon, nuts and parsley over filling.
Bake 20-25 minutes or until filling is set. Let stand 20 minutes before serving. Cut into wedges. Cover; store refrigerated.