Peel and finely chop the onion and garlic and sauté in hot oil. Add cream, bring to the boil and reduce to half over medium heat for ten minutes. Meanwhile, cook the tortellini in boiling salted water for twelve minutes and drain.
Grate 20 grams of Parmesan cheese, and use the peeler to slice the rest into shavings. Cut the ham into strips. Melt the grated cheese in the cream sauce. Add the ham strips and heat. Season the sauce with salt, pepper and nutmeg.
Mix with the tortellini and spread on plates. Add Parmesan shavings and serve garnished with basil leaves.