Slice the radicchio head and soak it in cold water for half hour, this will make it taste a bit less bitter.
Make the balsamic reduction by mixing together in a pan the red wine, balsamic vinegar, sugar and rosemary sprig, bring to boil and then let it simmer until it gets syrup texture.
Crumble the cheese, chop the walnuts halves into small pieces and slice the pear into quarters, heat up a pan with the butter and pan fry the pear quarters until golden brown. In the meantime prepare the salad dressing by mixing the olive oil, balsamic vinegar and dijon mustard, whisk to emulsify.
Drain and dry the radicchio, put it in a bowl together with the cheese, walnuts and the dressing, toss to mix, plate and top with the pears and the balsamic dressing.