Hi there!  I am going to attempt a topsy turvy cake for my daughters birthday next weekend.  I will do the part about cutting out the bottom to give the second tier a flat surface to sit on.

It will only be a two tier cake and will not be transported anywhere.  Do I need to use a dowel system like SPS?  I am going to do the top layer 6" and the bottom layer 10".

TIA!

I would say yes- do still put in the bottom supports. I only say that because my friend attempted the same thing last year and when she pulled back the curtain for her daughter's party to reveal the cake, it had collapsed on itself and her daughter burst into tears. Better safe than sorry. :-)

I wouldn't do that much work and then not support it properly.  Yes, it needs a board under the top tier and 3 or 4 supports in the bottom tier to support it.

I wouldn't do that much work and then not support it properly.  Yes, it needs a board under the top tier and 3 or 4 supports in the bottom tier to support it.

I wouldn't worry about the whole SPS but at least a board and straws, for sure.