Broccoli Rabe with Caramelized Onions

Have you ever cooked with broccoli rabe (usually pronounced "rob", also known as rapini)? It sort of looks like broccolini or Chinese broccoli, with longish stems, small green florets, and lots of leaves. It's actually more related to turnips than to broccoli, and tastes a little like mustard greens, slightly bitter but more nutty. Slightly bitter usually that is. The first time I cooked broccoli rabe it must have been really late in the season, because those greens were so bitter none of us (hardened bitter greens eaters that we are) could take more than one bite. ...