In a non-stick pan, sauté the finely chopped shallot in a drizzle of olive oil. Add the radicchio cut into strips and sauté in the pan for a few minutes; before removing from the heat, add a few tablespoons of vinegar and cook until evaporated; season with salt and pepper.
In a bowl, combine the radicchio with diced Grana Padano, slivers of pancetta, and a few thyme leaves. Cut down the length of the meat and open it like a book; beat it with a meat mallet until rectangular and 1 cm thick. Salt the meat and spread the radicchio, Grana Padano and pancetta on top.
Roll the meat tightly and tie with kitchen string. Season with salt and pepper and brown in a non-stick casserole dish with a drizzle of olive oil and a clove of garlic. Keep turning it around until golden brown on all sides, add a glass of white wine and let evaporate; add rosemary and thyme and cook over low heat for 25-30 minutes, turning it over every now and then.
Leave the meat to cool before slicing and serve with its cooking juices.