Heat the oven to 450 degrees. Brush a 10x15x1-inch pan with 1 tablespoon of the olive oil.
Arrange all of the vegetables in single layer in the pan. Drizzle with 2 tablespoons of the olive oil and sprinkle with salt. Bake for 10 to 12 minutes or until tender, turning over once.
Meanwhile, mix the pesto and sour cream in a small bowl. Spread the cut sides of the rolls with half of the sour cream mixture.
Divide the vegetables evenly on the bottoms of the rolls and top with a slice of cheese. Place the tops of the bread over cheese, sour cream pesto side down.
Heat a Panini press, contact grill or grill pan. Brush the outsides of the roll lightly with the remaining 1 tablespoon oil. Place the sandwiches in a Panini press or contact grill and close the lid. Grill for 4 to 5 minutes or until toasted and the cheese is melted.
Continue with remaining sandwiches. Alternative method: place the sandwiches on a grill pan on the stove top over medium heat. Press the sandwiches down with a spatula. Grill for 3 to 4 minutes on each side or until toasted and the cheese is melted, pressing down with a spatula. Serve the remaining pesto mixture with sandwiches. *Sandwiches may need to be grilled in 2 or more batches, depending on the size of the press or grill.