Spaghetti with homemade canned tomatoes

Name: Spaghetti with homemade canned tomatoes
Ingredients: 1 quart homemade canned tomatoes; 1/2 cup thinly sliced Vidalia onion; 1 tablespoon olive oil; 2 tablespoons butter; 3 pieces fresh garlic; 1/2 teaspoon salt to taste; 1 dash fresh ground pepper; 1 bunch fresh chopped basil; 1 bunch fresh chopped parsley; 1 pound good Italian spaghetti