Over medium heat, in a large saute pan, heat the olive oil and 1 tablespoon butter. Heat the oil for 1 minute. Add the onions, corn, salt, white pepper, and black pepper. Saute for 3 minutes. Using a wooden spoon, stir in the risotto. Saute for 2 minutes. Stir the stock into the risotto. Bring the liquid up to a simmer, about 6 minutes. Stir in the mushrooms and garlic. Simmer the risotto for 18 minutes, stirring constantly. Stir in the remaining butter, cream, grated cheese and truffle oil. Simmer for 2 minutes, stirring constantly. Remove from heat and serve. Garnish with shaved truffles.