just what the doctor ordered

Exactly what was needed. For example, This steak is just what the doctor ordered, or You've been a great help in our office—just what the doctor ordered. This expression alludes to a physician's prescription for a cure. [First half of 1900s]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.