What material can I use to make my own cake molds? I would like to make custom cake molds. 

I've asked about this in a few stores that specialize in cooking equipment, they said this wasn't possible. 

I wonder if 3D printing makes it possible. It would require a material that is food-safe, as per Which are the food-safe materials and how do I recognize them?

However, there are two extra conditions:


The material must be able to withstand the heat of an oven or microwave, and not mix with the dough.
It should not be too difficult to remove the cake from the mold after it is ready.


The first condition is where this question is a little different from Can you use PLA material with food and drinks? - that question is about cutlery and glasses, not about things that go into the oven or microwave.

Is there a material that can be used for this purpose?
I would say that FDM printing in general is out of the question for this task, ABS and PLA would both melt in the oven, and the grooves in the print from the FDM process would make it a nightmare to clean.

My initial thought was an SLA printer ( $1000+ ) which uses a Photopolymer Resin hardened by a UV light, and based on its medical uses, I would think that it is food safe - I do not know what its melting point is however.

Another idea, one that would not too easily be done in house, is porcelain. 

Shapeways offers a service that you could use for this - they say just $9 per part, 125 x 125 x 200mm maximum dimms, both food and oven safe.