@Jeruba Probably neither. In my lexicon, still-warm and pliable chocolate chips in a cookie would probably be called “gooey.”
Molten chocolate chips in a cookie implies to me dangerously too hot to want to eat.
I probably wouldn’t use the word melted for cookie chips unless they had flowed more than cookie chips usually do.
Chocolate is kind of expected to be melted or formed into shape for food, so in the case of chocolate, I might tend to expect that “melted chocolate” would still be warm enough to flow or ooze, or chocolate that had oozed around more than usual in a chip cookie. On the other hand, unless you eat your cookies soon, or keep them warm and gooey until eaten, they will eventually cool off, but since I expect chocolate to be formed, and usually chocolate chips in cookies don’t melt all that much, I would tend not to use the word melted to refer to them in their eventual cooled state.
Similarly, I would be afraid to eat a sandwich if someone said the cheese was still “molten”, but not a melted cheese sandwich.
Where I would use “melted” for cool objects, would be for things that are not expected to melt, such as chocolate bars or pens or headlights or plastic dolls or army men, who melted and then cooled off but are now deformed.
@smudges That’s a rule used to teach/get students not to make circular definitions. In that sentence I was not trying to define melted, but to explain a distinction between melted and molten, where the term melted itself is already assumed to be understood.