Clean and wash the radicchio lettuce; dry and cut into thin strips. Soften the chopped onion in a pan with the butter and oil; add the radicchio and leave to flavour for a couple of minutes, stirring. Add the rice and stir into the dressing for a minute; add a splash of Recioto wine and when this has evaporated, cook by incorporating the necessary broth a little at a time. After 15 minutes, amalgamate the mascarpone cheese and leave on the flame for another three minutes. Add salt and pepper to taste and add the grated Parmesan cheese.