Melt the butter in a small pan and mix in the flour. Stir in a little bit of milk at a time, then add the Parmigiano and season with black pepper. Cook on low heat for 3-4 minutes.
Cook the cappelletti for 2 minutes in salted boiling water. Drain, plate up then pour the Parmigiano sauce on top.
Complete the dish with some drops of balsamic vinegar and a sprinkle of fresh parsley.