Pasta and White Beans Gratin

2 cups uncooked pasta shells
2 cups loosely packed fresh basil
3 cloves garlic
1 cup grated Parmesan cheese 1 teaspoon olive oil
1 cup ricotta cheese 1/2 cup chopped onion 3 sprigs fresh thyme
1 bay leaf
1 tablespoon olive oil
2 (15 ounce) cans white beans 1 tablespoon balsamic vinegar salt and pepper to taste
2 tomatoes, chopped 1/2 cup bread crumbs 1 tablespoon olive oil

Bring a large pot of water to a boil. Cook pasta in boiling water until done. Drain, and set aside. Meanwhile mince basil and garlic with Parmesan cheese. Transfer to a medium bowl, and mix with 1 teaspoon olive oil. Mix in ricotta.
In a saucepan, cook onions with thyme and bay leaf in 1 tablespoon olive oil. Stir in beans and balsamic vinegar, and simmer for 20 minutes. Season to taste with salt and pepper.
Preheat oven to 350 degrees F (175 degrees C). Combine beans, tomatoes, and pasta in a well oiled 2 quart casserole dish. Place spoonfuls of the ricotta mixture in the pasta and beans, and press down to cover. In a small bowl, moisten bread crumbs with 1 tablespoon olive oil, and sprinkle over casserole.
Bake in preheated oven for 30 minutes, or until hot and bubbly.