Heat the oil in a non-sticking frying pan, and sauté the shallots for 2-3 minutes.
Lower the flame, season with salt and pepper, sprinkle with sugar and vinegar and simmer gently for a few more minutes until thick and syrupy.
In the meantime, cook the Tortelloni according to package instructions and drain, reserving a ladleful of the pasta cooking water. Add the pasta to the pan with the shallots, stir gently, adding some of the pasta water if you need to loosen the sauce. Season to taste.
Divide among 2 plates, sprinkle with Parmigiano Reggiano shavings and serve.