Terrine Cooked in Bain Marie
Answer: Unless a recipe specifically calls for preheating, you should be fine starting with cool water. It may be even recommended to start out cool for egg dishes, otherwise you may end up with a crusty effect.
The whole point of a bain marie is to gradually heat and cook a dish, so starting out cooler should pose no problems in the majority of cases.
P.S. That is a photo of yummy salmon terrine
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