Bring the broth to a simmer in a heavy medium saucepan. Keep the broth over low heat. Boil one cup of
water and add the porcini mushrooms - set aside for 10 minutes till the mushrooms are tender. Melt half the butter in a heavy saucepan. Add the olive oil. Add the onions and saute until tender, about
8 minutes. Add the baby bella and shitake mushrooms. Remove the porcini mushrooms, finely chop and
add to the saucepan. Once the mushrooms juices evaporate add the Arborio rice and toast for 2 minutes. Add 3/4 of the porcini mushroom broth, one cup of hot broth, white wine and truffle oil and simmer over medium heat stirring about every 4- 5 minutes. As the broth evaporates add another cup of hot broth and continue to stir the rice. Add salt and pepper to taste. Continue to cook until the rice is tender and the mixture is creamy, about 30 minutes (the rice will absorb 8-9 cups of broth). Turn off the gas. Mix in the Parmesan cheese and remaining butter.