Cut the ham into strips. Wash basil, shake dry, pluck leaves from the stalks and chop. Melt butter in a large pot. Stir in flour and sweat lightly. Deglaze with cream and milk, bring to the boil and simmer while stirring for about 5 minutes.
Stir the sauce best with a whisk, so that no lumps form. Stir in ham and basil. Season to taste with salt and pepper.
Bring plenty of salt water to the boil in a large pot. Prepare the tortelloni in it according to the instructions on the packet. Then pour into a sieve. Put the tortelloni back into the pot. Add the sauce and mix with the tortelloni.
Arrange on plates, sprinkle with parmesan.