Cake, Candles, And Child's Face

How can you capture it all beautiful--without flash?

With Flash                                                With IS lens

Flash sometimes destroy the mood of the room.
Consider using available light instead (with Canon EF-S 17-85mm f/4-5.6 IS USM)

1. Since candlelight alone is not enough, put on some room light. Or keep the room somewhat dark, and let in light from another source (such as the room next door).
2. Set your zoom lens to a wide to normal angle (17-28mm), which has a shorter focal length.
3. Choose the Av exposure mode and keep the aperture fully open.
4. When aiming at the subject, put your elbow(s) on the table (or somewhere else) to hold the camera steady as you focus on the child's eyes. To prevent blurring, try to press the shutter button when your child is relative still