Food Safe Plaster-Like Material Does anyone know of a hard, heavy, moldable material (like plaster or cement) that is also food safe? I’m looking for something to make bowls and cups without kiln firing like I would have to with clay.
Food safe, moldable materials are rare in general. The closest thing that comes to my mind is a kind or "organic plastic" made from milk, but it looked hard to work with and I don't know how food safe that really is on the long run.

Take for example a simple porcelain dish: the porcelain itself is porous and would stain with food residue. It's the glaze that makes it food safe.

I suggest using whatever clay is best suited for the style of bowls you want to create, then applying a food safe varnish or lacquer in several coats to seal the surface.