Place the stock in a medium saucepan over medium heat.
Bring to a simmer.
Immediately lower the heat to keep the stock very hot but not boiling.
Heat 2 tablespoons of the butter in a large shallow saucepan over medium heat.
Add the shallot and garlic along with a pinch of salt.
Cook, stirring frequently with a wooden spoon, for about 4 minutes or until the shallot is soft and translucent.
Stir in the rice and cook, stirring frequently, for about 5 minutes or until the rice is almost chalky in color and glistening.
Add the champagne and cook, stirring constantly, for about 5 minutes or until the wine has been absorbed by the rice.
Begin adding the hot stock, about 1 cup at a time, and cook, stirring constantly, until the liquid has been absorbed by the rice.
Do not add additional stock until the previous cup has been absorbed.
Keep adding stock and stirring until the rice is al dente and a creamy “sauce” has formed.
Stir in the heavy cream.
Add the remaining 3 tablespoons butter along with the Parmesan.
Season with salt and white pepper to taste.
When ready to serve, ladle out equal portions into large shallow soup bowls and shave the truffles over the top of each.
When truffles are not available you can make a wild mushroom risotto, sautéing porcini or chanterelles separately and then folding them into the rice at the last moment.