I am the Kat that Walks By Itself

I wouldn't put gelatine in anyway
I was following the advice of various ice-cream recipes I found online.

So you can substitute alcohol for it?
No, the alcohol is in place of the salt+water mixture which is required to put between the fixed and the removable bowl so that it freezes properly.

The Optifast ice cream sounds rather nice.
It is. With so much cinnamon, it completely overwhelms the original taste. I just had the second half of the batch I made last night. The downside of putting it in the freezer is that it had frozen solid. So I put it in the microwave on medium, and then it melted too much. Oh well.

I haven't heard of cassia cinnamon; I should ask at the health shop.
It might be called "Dutch cinnamon"