Reflectors can be great tools for a variety of shots. They're inexpensive, simple to use, and can provide the dark side of your subject with just enough light to make the photo. For this shot, I placed a large silver reflector opposite a north-facing window. This combination eliminated the need for an artificial light source and was fast & effective.
On my son's 2nd birthday, I dressed him in a silk jacket I had purchased for him while in Shanghai. I asked him to stand by the window and quickly went to work, knowing that he stays in any one position for a maximum of 0.2 seconds before becoming interested in something out of reach. Behind him I placed a large black collapsible background to eliminate any distractions and to present more of a clean image. And, to camera-left, I placed my reflector. The light coming in through the window not only lit the left side of my son's face but also bounced off the reflector, giving the right side of his face just enough light so as to not be lost in shadows.
I told him to look right in 'dad's camera' and he went to work, hamming it up...
Normally I'd reach right for my SB Speedlights when setting up an indoor portrait. However, if and when I remember to use the natural resources available, the outcome is almost always exceeds the 'fake' alternative.