Using the durable 3d recipe, I made 2-9x13 cakes. One baked and settled to approximately 1 3/4" high, the other 2" high. I am making a suitcase cake and I want 2- 2" (ish) layers of cake with one layer of filling a la Sharon Zambito. Do I need to put bubble tea straws in the bottom cake to support the top one? Thanks for your help!

If I understand you correctly, no you don't need supports for the bottom 2" layer. Sounds like you are just making a regular 2-layer cake. If you were to make another suitcase on top of that one (adding another tier) then you would need supports below that tier.

Thought so but just wanted to make sure. Thanks!