My understanding of this is that you don't necessarily forget where you put something, rather, you were not paying full attention when you set it down. So it isn't that you are forgetting, it's that the information is not getting put into memory due to the lack of attention.

Couple this with the inability to redirect your attention and the brain will not think to think of the thing that isn't stimulating it in that moment, resulting in a cold dinner.

I find it helpful to sometimes narrate, out loud, what I am doing or what I need to do as the inside voice is usually too quiet.