“Cavolo” (cà·vo·lo, the stress on the “a”) i.e. cabbage is a common and healthy ingredient in many recipes of the Italian cuisine. It is included in the cancer prevention diet, and despite the bad smell it releases, due to the presence of sulphur compounds, it’s employed as a side dish, in potages, in vegetable pies and so forth.

The Italian language, too, employs the word in many different ways. “Come i cavoli a merenda” (co-me i cà·vo·li a me·rèn·da) – literally “like cabbages for tea break”, whose real meaning is to stand out like a sore thumb, or do not match with something.
It’s a very common idiom when you need to express that something or someone does not fit into the context or does not clearly harmonize with the surrounding.

As a matter of fact, whoever fancies cabbages for tea? Nobody – in Italy, at least.

The word cavolo is frequently used in a figurative sense, as a substitute for the impolite – but very frequent word  – c*zz* (male organ) NOT be used in formal speech.

So that:

• the vulgar “d*ckh**d” becomes a milder “testa di cavolo” (tè·sta di cà·vo·lo),
• the expression “I don’t/couldn’t give a monkey’s” translates into “non me ne importa un cavolo” (non mé né im-pòr-ta un cà·vo·lo), and
• the rude interjection “no f*ck*ng way!” becomes a gentler “col cavolo!“.

If you can manage to work out an awkward situation with benefits for all the parties involved, you will be able to “salvare capra e cavoli” (sal-và-rɛ cà-pra ɛ cà·vo·li) – literally “to save both goat and cabbages”, i.e. run with the hare and hunt with the hounds.

It is a frequently used idiom, or rather, it is a very frequent wish, because very often either you save the “capra” or the “cavoli“. Nine times out of ten you can’t have your cake and eat it, too.
Perhaps you could have some cavoli for lunch or dinner (not for tea).