Heat chicken broth to simmering in a small saucepan and leave on very low heat. In a heavy- based, wide saucepan heat olive oil, add onions and cook until golden over medium heat. Add rice and stir to coat each and every grain with oil. Add the wine and cook until it has evaporated. Begin by adding 1 cup of hot stock, stirring with a wooden spoon to mix. Allow this liquid to be absorbed, then add 1/2 cup stock, stirring until evaporated. Continue to add broth by 1/2 cupfuls, stirring after each addition. Continue until rice begins to soften. Last addition of stock should just absorb into rice, leaving it slightly tight. Stirring quickly with a wooden spoon, add butter and cream. Risotto will become very creamy. Stir in herbs and cheese. Remove from heat and adjust seasoning to taste. Serve topped with freshly-grated cheese and drizzle with truffle oil, if using.