Cook the penne in a large pan of salted water, drain and return to the pan.
While the pasta is cooking, sweat the onion and garlic gently in a little oil until just soft and remove from the pan. Turn up the heat and add the pancetta, chilli and radicchio. Cook for a few minutes.
Add the wine, stock and reduce, add the cream and cook for a few minutes more. Add the mascarpone, lemon juice and zest and mix well.
Add the radicchio mixture to the cooked pasta and stir well. Tip into a bowl, scatter with parsley and shavings of parmesan and serve immediately.