Gnocchi with Spicy Sausage, Caramelized Onions, and Broccoli Rabe

Sausage, spicy

bunch Broccoli rabe

Flat-leaf parsley, loosely packed leaves

Onion, medium

Sarah mastracco's potato gnocchi

Salt and freshly ground pepper, Coarse

Sugar

Olive oil

Red-wine vinegar

Butter, unsalted

Parmesan cheese, grated