Brassica oleracea var. gemmifera, also called cavoletto di Bruxelles.
The plural form, which is almost always used, is cavolini and cavoletti, respectively.
I was 22 years old and living in Milan the first time I ate cavolini di Bruxelles alla parmigiana at a friend's house, steamed and lightly seasoned with butter and parmigiano. I liked them then and still do. I am aware that in this country they get mixed reviews. I believe the trick is to offset their soft nature (when steamed) with something crunchy, like toasted hazelnuts or almonds, or to enhance their flavor with cheese (like, for example in cavolini gratinati, gratin).
Cavolino means small cavolo and there are many kinds of cavoli, which I will describe in future posts. Recently I learned that, besides the well-known green variety, there is also a purple variety: I don't know yet what these cavolini taste like, but the plant is lovely, as you can see here and here (two photos from our community garden).
The English expression 'mind your own business' has a literal translation in the Italian fatti gli affari tuoi. However, going down the path of increasing rudeness, the next stop is fatti i cavoletti tuoi. This is an expression I used a lot as a child when quarreling with my brother. It is actually a euphemism for a much ruder expression, which belongs to the category of definite no-nos.
This is my entry for Weekend Herb Blogging, a food blogging event started by Kalyn's Kitchen, hosted this week by Mele Cotte, a lovely Italian name which I am including in my audio snippet. Here's the roundup of WHB #90.