I forgot the butter in the microwave....so needless to say the butter did not get in the cake mix.......Im doing a double square cake and the top layer is the one, the butter got left out.  I did notice the cake was slightly larger than the one that had the butter so i cut to size.  The cake looked fine but will it taste fine?

Are you selling this? If so, I would remake it. It they wanted a two layer cake with both layers the same, they are going to taste different.

If it is for you, I would just taste it. 

Nancy

If you're selling it, I wouldn't take the chance and give it to someone. Just remake it. But if its for you, you should try and see if it tastes fine.

AThird

Fat is a tenderizer so the cake will not have the correct texture (and obviously not the same flavor). Ditto the posts above - if the cake is for a customer, you should make a replacement.