Broccoli rabe (rapini) has a bitter and peppery taste. It's not very much like broccoli, flavor-wise. If you don't enjoy bitter flavors, you may want to substitute with a less pungent green vegetable, like kale (de-stem, and cook in the pasta water for only 2 minutes instead of 5), or spinach (don't pre-cook at all).
This dish works best with a spicy and garlicky sauce to act as a counterpoint to the bitterness of the rapini.
Baked Broccoli Rabe and Cauliflower Stuffed Shells originally printed from https://yupitsvegan.com/baked-broccoli-rabe-cauliflower-stuffed-shells/ February 17, 2015