Wash, drain and detach radicchio leaves. Prepare raspberry vinaigrette as follows: Cook 1 cup (metric cup = 250 ml) of raspberries in 80 ml of white vinegar for about 15 minutes, stirring occasionally. Remove from heat. Add 160 ml of olive oil, ½ cup of brown sugar, two cloves of finely chopped garlic, salt, pepper and a little basil. Mix together in food processor, then strain. Refrigerate for at least 30 minutes. Drizzle over radicchio leaves.