Pulse tomatoes and juices in a food processor until coarsely chopped.
Heat garlic and oil in a 5-quart pot over medium heat until garlic begins to sizzle, about 2 minutes. Add tomato puree, salt, and pepper, and bring to a boil. Reduce heat, and simmer, partially covered, stirring occasionally, for 30 minutes. Let cool slightly. Sauce can be refrigerated, covered, for up to 3 days.