Heat the olive oil in a saucepan; add chopped onion, thyme, rice and sauté for a couple of minutes and pour white wine into it. Cook the rice for 15-16 minutes, adding some vegetable broth from time to time. When the rice is nearly cooked, add Mascarpone, chopped Radicchio salad, lemon rind, a pinch of white pepper and stir it then cover it and leave it to whisk for 4-5 minutes before serving.