Bring a large pot of salted water to a boil.
Add the olive oil and sausage to a large nonstick skillet. Heat over medium-high heat and cook for 8-10 minutes until browned. Take care to break up the sausage into small pieces with your spatula.
Meanwhile, cook the pasta in the boiling water according to package directions, usually about 10 minutes.
Add the garlic and fennel fronds to the sausage and cook for 3-5 minutes more until garlic is fragrant. Then reduce the heat to low.
Reserve ¼ cup of pasta cooking water and drain the rest of the pasta.
Add the cooking water and pasta to the skillet and stir to combine. Sprinkle on the cheese and toss again to combine.
Season with pepper and serve (with additional cheese if desired).
