melt in one's mouth

melt in (one's)/the mouth

Of food, to be soft or tender, and, typically, delicious. The phrase is often quite literal. This decadent chocolate cake positively melts in the mouth. I've never had such a perfect steak in my life! I swear, it melted in my mouth.
See also: melt, mouth

melt in one's mouth

Taste very good, as in This cake is wonderful-it just melts in one's mouth. This expression, first recorded in 1693, at first alluded to the tenderness of some food that therefore did not require chewing, but it had acquired its present meaning by about 1850. Also see butter wouldn't melt.
See also: melt, mouth