Not only does it keep your loaf moist -- that's in part because of the sauce's low water content ... a hearty helping of pesto alone. Given how long pesto lasts once it's opened, this could ...

At the beginning of the 20th century, chef Auguste Escoffier began a system of organizing sauces which led to the five French ...

but proper tomato sauce is deceptively complex, and it's cooked for a long time. It includes fried salt pork, vegetables, and a roux -- and that's before the tomatoes even get poured in.