A cross between broccoli and gai-lan (Chinese broccoli), and, in actual fact, is a copyrighted brand name. Instead of the thick stalks and large head of broccoli, broccolini is made of slender stalks with small florets and has a sweeter, tender stalk. Substitute with broccoli, altering the flavour and texture of your stir-fry slightly. Slice broccoli in smaller pieces to get closer to the appearance of broccolini. Or try rapini, also known as broccoli rabe, which is very similar to broccolini, but has a nuttier, more bitter taste.