Glasbake was made by McKee Glass Co. from depression era to 60`s I think !! The fish dishes by them are not hard to find !! Yours looks to be from 50`s !! Can you tell me what the design number is on the bottom ??
Wait a minute,, you said porcelain ?? Don`t know that they ever made a pottery type !! Can you take a good clear shot of that bottom mark !! Can`t read the one here !! Still need that style number !!