In a wide pan, heat 3 tbsp olive oil. Add all mushrooms together with the onion and garlic. Sauté over medium-high heat until lightly caramelized and they release their juices (6-7 minutes). This will be the flavor base for the risotto.
Add the Aquarello rice, stir well for 1-2 minutes until it becomes glossy.
Pour in the white wine, stir, and let it fully evaporate.
Start adding the hot water, one ladle at a time, stirring continuously. Do not add all the water at once - each time the liquid is absorbed, add more. This way, the rice absorbs all the flavors. Total cooking time: 16–18 minutes until al dente.
Remove from heat. Add the butter and Pecorino, then stir vigorously until creamy. Adjust with salt and freshly ground pepper.
Divide the risotto into deep plates, grate fresh black truffle on top, and drizzle with a little raw olive oil for extra aroma.