Add water, skins of Portobello mushrooms, thyme and bay leaf in a pot. Boil for 10 minutes and strain. This is your mushroom stock for the risotto.
Cult Portobello and 2 white mushrooms in slices and sauté in a hot pan with olive oil until all liquid evaporates. Add chopped onion and garlic and sauté along with mushrooms. Add Arborio rice and stir well. Add salt and reduce with white wine.
Begin your procedure for risotto. Add 1-2 of mushroom stock into the pan and keep stirring. Repeat the procedure until all the mushroom stock has been used.
In the meantime, marinate 2 white mushrooms in olive oil, salt and chives in order to use them to garnish your risotto.
Turn off heat and add butter and parmesan into the pan to make your risotto moist and velvety. Drizzle a little bit of truffle oil and garnish with chopped basil and marinated white mushrooms.