I have been asked to make a cake like this. I will be using a glass vase type thing between the layers like in the pic. When I set the cake up is there something I can do to make the upper cake more stable than just sitting it on the vase.

BTW the cake is from Publix.

TIA

You can line the bottom of the support plate with non-skid fabric to prevent slipping, OR use poster stickum (removable gunk) to hold it in place.