Chop the rapini into 1" pieces, then blanch in a large pot of well salted boiling water for 30 seconds. Use a spider strainer to scoop into a paper towel lined bowl and set aside.
Cook the orecchiette pasta in the same water you blanched the rapini in until desired doneness. Reserve 1 cup of pasta water and strain the pasta. Toss in a little bit of oil and set aside.
In a large non-stick pan over medium-high, heat olive oil and cook the Italian sausage until browned and well crumbled. Add in the rapini and sauté for another minute.
Over medium low heat, pour in the reserved pasta water and add drained, cooked orecchiette to the pan. Stir in butter and toss until melted and emulsified.
Kill the heat and add in grated parmesan. Toss to combine.
Plate up and garnish with a sprinkle of additional parmesan, some cracked black pepper, and a sprinkle of red chili flakes.