What could be more tasty and enticing than a steaming bowl of this noodly, beefy, aromatic Vietnamese specialty? Left to simmer in the crock pot all day, it will fill your home with mouthwatering smells that will greet you the minute you walk through the door. Don't forget all the requisite garnishes that elevate its diverse flavor profile even more: sliced onions, bird's eye chilies, fresh herbs, bean sprouts and a lime wedge for the finishing tang.