From what I've seen cake smash images are very evenly and softly lit so I'd be tempted to see if there are plain walls to bounce off so the light is very diffused and walls make great big light sources. Again without knowing the location it's hard but I'm guessing as it's a cake smash it isn't going to be on a carpet so is the floor wooden laminate or tiles? You may get away with a single softbox high up, square on, pointing down to the subject. Depending on the floor this may act as a reflector to bounce light back in to soften the shadows. Until you get there you won't know. Don't make things over complicated, look for natural light first, is that do-able and does it look evenly lit with a fast enough shutter? If not then add a single light and see how that looks. If it doesn't work then look to work out why, is it placement of light source etc? Does tweaking it work in terms of power, placement etc. If not then will a second light source then fix it?
Hoping that makes sense, I'm guessing others will be along to help out that may have further better advice
