Roasted Vegetable Baked Ziti

Name: Roasted Vegetable Baked Ziti
Ingredients: 2 tablespoons butter; 2 tablespoons flour; 2 cups vegetable stock; 1 medium onion, poked with a fork; 3 tablespoons Parmesan cheese; Salt and pepper; 2 pounds plum tomatoes, seeded, quartered; 2 medium Italian eggplant, quartered, sliced; 2 large red bell peppers, seeded, quartered; 1 large Spanish onion, halved, cut into eighths; 4 cloves garlic, chopped; 1/4 cup calamata olives, pitted, sliced; 2 tablespoons olive oil; 1 pound ziti pasta, cooked al dente, drained; 1 pound mozzarella cheese, sliced thin; 1/2 cup grated Parmesan cheese