1/200 s at F/3.5, ISO 100, focal length: 50mm, Camera set to manual, external speedlight controlled with built-in transmitter. Speedlight diffuser made from a white plastic carrier bag :)
I have no idea how they do it (by they I mean professional photographers who do portrait passport photographs) but we almost ended up in tears, both. Currently required biometric photograph is an almost impossible task, when your client is six and cannot sit still for more than 2 seconds. Trying to focus, while manually straightening her head, while keeping the hair from the face, while begging to change that silly smile to something more conventional...
Frankly, every other picture from this shoot would make an excellent poster for an anti-child-abuse campaign.