1Heat oven to 450ºF. Spray jelly roll pan, 15 1/2x10 1/2x1 inch, with cooking spray. Toss bell peppers and mushrooms with oil in pan. Bake uncovered 15 to 20 minutes or until crisp-tender. Refrigerate 15 minutes to chill.
2Coarsely chop roasted vegetables. Mix chopped vegetables, parsley and 2 tablespoons mayonnaise; set aside. Mix chicken, 1/2 cup mayonnaise and the pesto.
3Cut bread horizontally into 4 layers. Place bottom layer on plate or tray. Spread with half of the pesto filling. Top with bread layer. Spoon vegetable filling over bread layer. Top with bread layer. Spread with remaining pesto filling. Top with remaining bread layer.
4Spread cream cheese over outside of sandwich loaf. Refrigerate at least 1 hour before serving. Garnish loaf with fresh herbs. Cut into 8 slices; cut each slice in half. Store covered in refrigerator.