Heat olive oil in a heavy pan over medium heat. Saut� onion in oil. Add the rice and stir until well coated with oil. Reduce the heat to low.

Slowly add white wine, stirring constantly, until wine is absorbed. Add chicken broth 1/2 cup at a time, stirring frequently, until rice is creamy and still slightly firm. (You may not use quite all the broth, but don't let the rice dry out.)

Stir in softened truffle butter. Add Parmesan cheese, shaved truffles or sauteed mushrooms, if desired. Add salt and pepper to taste. Sprinkle with minced parsley.

Serve immediately. Makes 4-6 servings.