The TSA still has not defined a gel for me.

I doubt that your marzipan is a gel, a colloidal substance (which may or may not be a gel) or a liquid.

In fact, it is clear that is is not a liquid. But is it a gel? I would argue with the TSA that you cannot define a gel unless you have measured its viscosity.

And that is assuming that the material is Newtonian, because is your marzipan is non-Newtonian, good luck with your viscosity measurement, but I am digressing.

So that being said, assuming you have obtained a viscosity measurement for marzipan, and assume that it is 10E13 Poise, you'd have a good argument that your Marzipan is a solid.

As the TSA to prove that it is a gel, not a solid, by asking them to provide you with a viscosity measurement.

I suspect that marzipan is non-newtonian, in any case. It may even be thixotropic.