kmw, that is great! So encouraging to hear
Your cake looks awesome. Did you end up using the beetroot or did you ditch it?
Yes Tasty, tapioca flour and starch are the same thing.... but potato starch vs flour are different. Also corn starch vs flour is named differently between USA and UK/Aust. I use pure 100% corn starch - white - rather than wheaten starch or maize flour, which is a yellow colour, and not starchy.
It all gets a bit confusing. lol.