Preheat oven to 425°F. Line a baking sheet with parchment.
Bring a few inches of water to a boil in a deep skillet or pot. Salt water, add broccoli rabe and cook 4-5 minutes. Drain, cool and chop.
Place sausage in a bowl. Squeeze excess liquid from the breadcrumbs then add to sausage along with the chopped broccoli rabe, egg yolks, parsley, lemon zest, garlic, grated cheese and EVOO. Use a small scoop to form 2-inch meatballs, arranging them on the parchment-lined sheet as you go. Transfer to oven and roast to golden and cooked through, about 15-18 minutes.