1. Combine water, porcini mushrooms, onion, celery, carrot, bay leaf, and salt in a saucepan. Bring to a boil, reduce heat and gently simmer for 30 minutes. Strain, pressing on solids to extract as much liquid as possible, you should have about 6 cups. Discard solids and return broth to saucepan and keep warm.
2. Melt 2 tablespoons butter with 1 tablespoon oil in a heavy saucepan or Dutch oven over medium heat. Add fresh mushrooms and cook until tender and slightly browned in spots, about 5 minutes. Season with salt then transfer to a plate and keep warm.
3. Add 1 tablespoon butter and remaining 2 tablespoons oil to now empty saucepan over medium heat. Add shallot and cook until translucent, about 3 minutes. Add rice and cook, stirring, until thoroughly coated. Add wine and cook, stirring constantly and thoroughly (making sure no rice is sticking) until absorbed, about 5 minutes.
4. Add ½ cup porcini broth and cook, stirring constantly and thoroughly, until fully absorbed. Continue adding broth ½ cup at a time stirring continuously and waiting until fully absorbed before adding more, until rice is al dente, about 20–30 minutes. Make sure to taste often as you cook to ensure you don’t overcook (or undercook) the grains.
5. Once rice is tender but still firm to the bite, add parmesan and remaining 2 tablespoons butter, stirring rapidly to coat the grains. Remove from heat and season with salt. Serve immediately topped with sauteed mushrooms, shaved cheese, and herbs.