The most common and most likely answer to this crossword clue is the 6 letter word SPONGE
I've seen this crossword clue in The Guardian
S
P
O
N
G
E
Buddy explains!
The straight part
We know that "Cake" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cake = sponge.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SPONGE mean?
SPONGE noun- Any of various marine invertebrates, mostly of the phylum Porifera, that have a porous skeleton often of silica.
- A piece of porous material used for washing (originally made from the invertebrates, now often made of plastic).
- A porous material such as sponges consist of.
- A heavy drinker.
- A type of light cake.
- A type of steamed pudding.
- A person who takes advantage of the generosity of others (abstractly imagined to absorb or soak up the money or efforts of others like a sponge).
- A form of contraception that is inserted vaginally; a contraceptive sponge.
- Any sponge-like substance.
- A mop for cleaning the bore of a cannon after a discharge. It consists of a cylinder of wood, covered with sheepskin with the wool on, or cloth with a heavy looped nap, and having a handle, or staff.
- The extremity, or point, of a horseshoe, corresponding to the heel.
- A nuclear power plant worker routinely exposed to radiation.
- To take advantage of the kindness of others.
- To get by imposition; to scrounge.
- To deprive (somebody) of something by imposition.
- To clean, soak up, or dab with a sponge.
- To suck in, or imbibe, like a sponge.
- To wipe out with a sponge, as letters or writing; to efface; to destroy all trace of.
- To be converted, as dough, into a light, spongy mass by the agency of yeast or leaven.