1. Bring a few inches of water in a deep skillet to a boil. Season with salt and add rapini/broccoli rabe, cook 3 minutes and drain.
2. Return pan to heat and add olive oil, 3 turns of the pan. Add red pepper and garlic, stir for a minute. Add broccoli rabe and toss 2-3 minutes more; salt to taste.
3. Preheat grill to medium heat. Form the sausage meat into four 4-inch patties, about 3/4 inch thick. Brush the burgers with oil and grill over medium heat until browned and crusty on the bottom, about 5 minutes. Carefully flip the burgers.
4. Top with the cheese and grill until the burgers are cooked through and the cheese is melted, about 5 minutes longer. Spread the pesto on the rolls. Top with the burgers and broccoli rabe. Enjoy!