Is a jaffacake a cake or a biscuit??

It will help you immensely when seeking discussions on-line to know that typing your text in all capital letters is considered the equivalent of shouting. People are far less likely to respond to someone they see as yelling at them.

Then, of course, there is the problem that your question is a little bit incoherent.

Can be made into Bite-sized biscuits or a full cake.

According to UK tax laws, the definitive answer is that it is a cake and does not attract VAT, whereas chocolate biscuits do.

Note for non-Brits: a "Jaffa Cake", two words, capital J, capital C, is best known as a product made by McVitie and Price in the UK since 1927. It has three layers: a sponge base, a layer of orange flavoured jam and a coating of chocolate. The cake-or-biscuit question was answered for some purposes in a 1991 tax tribunal case. The UK tax authorities had decided that a Jaffa Cake was a biscuit, not a cake, and thus liable to Value Added Tax. McVities appealed and won, so Jaffa Cakes kept their untaxed status. In the United Kingdom, VAT is payable on chocolate-covered biscuits, but not on chocolate-covered cakes. McVities never registered the "Jaffa Cake" name, so anybody can sell products with that name, and it become kind of generic.

On QI they spoke about the court case, what was the decider was the staleness ness. Biscuits go soft when stale, cakes go hard, Jaffa cakes go hard therefore they're cakes.