Put a large sauté pan over a medium flame and heat the oil.
Add the sausage and sauté while breaking it apart with a wooden spoon. Once the sausage is browned, about 5 minutes add the shallot. Cook until the shallot has softened a bit, about 3-4 minutes.
Add the radicchio to the pan and sauté until softened, about 5 minutes.
Add the cream to the pan and heat it almost to a boil. Lower the heat to a simmer and add the nutmeg.
Drop the garganelli into a large pot of generously salted boiling water. Cook until al dente.
Drain and add to the pan with the sauce. Toss for 1-2 minutes over a medium flame.
Remove from heat and add the grated cheese allowing the residual heat of the pan to melt the cheese. Add some fresh black pepper as desired.