Place garlic and shallots in an 8-inch square pan lined with aluminum foil; drizzle with oil.
Bake at 450° for 15 minutes, stirring twice; cool.
Process garlic, shallots, tomatoes, 3/4 cup chicken broth, and next 5 ingredients in a blender or food processor until smooth, stopping to scrape down sides.
Cook tomato mixture and remaining 3/4 cup broth in a medium saucepan over medium heat 5 minutes or until thoroughly heated. Stir in basil; serve immediately with Basil Pesto Toast, if desired.
Note: To serve 4, double all ingredients. Process half each of garlic, shallots, and tomatoes with 1 cup broth in blender; repeat. Heat tomato mixture and remaining 1 cup broth in a large sacucepan for 8 minutes.