In a large skillet over medium heat, add the oil and the sliced sausage.

Cook, turning occasionally until browned and crisp around the edges – about 15 minutes.

Remove the sausage to a plate. Reserve the pan drippings.  Set aside.

Meanwhile, bring a large pot of water to a full rolling boil.  Add a handful of Kosher salt to the pot and return to a boil.

Toss in the broccoli rabe and cook, uncovered, until the vegetable is bright green and just tender, but still a bit crisp – about 5 minutes.

Use tongs to remove the broccoli rabe to a fine mesh colander. Chop into bite-size pieces.

Add the pasta to the boiling water.  Cook, stirring occasionally, until al dente – about 12 minutes.

Meanwhile, in the skillet, warm the pan drippings.  Add the garlic and cook until it is golden brown – about 5 minutes. If desired, stir in the red pepper flakes and cook for an additional minute.

Add the broccoli rabe and sausage to the pan.  Toss with the garlic and cook until warm.

Drain the pasta in a colander, but reserve the cooking liquid.

Add the pasta with ¼ cup of the pasta water to the skillet.

Toss with the sausage and broccoli rabe.

Stir in the grated cheese.  Stir vigorously until the cheese is melted and a creamy sauce has formed.

Transfer the pasta to a serving bowl.  

Top the pasta with a mound of ricotta cheese.

Sprinkle with the shaved Italian cheese.

Serve the pasta warm with a spoonful of ricotta cheese on top, if desired.

Garnish with a sprinkling of additional Parmesan cheese and chopped, fresh parsley.