Most traditional chicken soup recipes are simmered for hours, producing a flavorful broth as well as overcooked, insipid chicken (usually discarded as a byproduct). This recipe avoids that wastefulness, and the result is flavorful, moist chicken along with a rich broth and intact vegetables.
Browning the chicken and vegetables builds flavor, and because sous vide cooking sidesteps evaporation, only a small amount of water is needed, producing a concentrated stock. Sous vide also allows us to cook steadily below a simmer, meaning the chicken and vegetables won’t overcook while they impart their flavor to the broth.
All explanations aside, this is a fast, easy technique to make an extremely satisfying chicken soup. The dumplings don’t hurt, either.