Don't you love discovering a secret ingredient? Something that you would have never thought to add to a favorite dish, but after you taste it, you realize it was a really good idea?
One of my top ten in this category is black olives as an ingredient in minestrone, or any similar vegetable soup.
I remember exactly when and where I discovered this secret. We were in Cincinnati for the Metropolitan Opera Auditions, and on the way home we stopped at Pompilio's, a venerable old Italian restaurant in Newport, KY. In the minestrone we discovered the secret ingredient and loved it. Since then, I've often added olives to my soup. They add a little salt and a lot of concentrated flavor, and they look pretty.
Pitted kalamatas, which I can usually get at the olive bar in my local grocery, are perfect; sometimes I cut them into halves, other times serve them whole. If I can't find pitted, I'll sometimes get another fancy black olive and cut the pits out; it takes a while, but you need less because the pit-full varieties tend to be saltier and stronger.