Note: Kale can be used in place of broccoli rabe.
Note: If you can only find smaller bunches of broccoli rabe, then use two.
Note: You can substitute tomato paste and red chili flakes for harissa paste.
Note: You can use beans such as cannellini, butter or great Northern.
Note: Instead of preserved lemon, you can squeeze the juice of a fresh lemon.
Note: Instead of feta cheese, you could use queso fresco or pecorino.
Note: You can substitute cilantro for parsley.
Note: You can substitute slab bacon or leftover ham for sausage.