The background isn't empty at all, in fact, the photo would be ruined imho if there was anything there. I love the soft colors! The only thing I can think of to critique is the light. It seems you've used a very hard light. It "blows out" the left side of the cake tower. Also the shadow under the tower is really harsh. I think you'd get a better result using three lamps. It's very easily done, Just set them up in a triangle and try to make the light even and to make the shadows kinda disappear, and make the light softer taping regular notebook paper over them. Also, removing the crumbs would make it look more delicate.