You searched for: “bacronyms
bacronym, backronym (s) (noun); bacronyms, backronyms (pl)
Taking a word which already exists and creating a phrase, usually humorous, using the letters of the word as initials; and so the process is the opposite of producing an acronym.

Here is an example of a bacronym: SURFSIDE: Small Unified Reactor Facility with Systems for Isotopes, Desalting, and Electricity.

—Bob Levey, "When You Can't Decide, You Just Pick Them All",
The Washington Post, November 8, 1983.

Another example of a bacronym: BANANA or "Build Absolutely Nothing Anywhere Near Anybody"; and GOD or "Guaranteed Overnight Delivery".