extra virgin olive oil, oyster mushrooms , fibrous stems removed, mushrooms torn in half if very large, button mushrooms, cleaned and sliced, kosher salt and freshly ground pepper, shallot, finely diced, butter, extra virgin olive oil, mushroom , vegetable, or chicken broth, water, arborio rice, grated parmigiano-reggiano, plus more for serving, parsley, very finely chopped, procedure, combine the broth and the water in a medium saucepan and heat to simmer over medium heat., in a large, heavy saute pan, heat 3 tbsp of extra virgin olive oil over high heat until very hot, but not quite smoking., add about 1/3 of the mushrooms , taking care not to crowd the pan. saute the mushrooms over high heat until golden brown in spots, adding a small pinch of salt halfway through cooking., sauteed mushrooms with a slotted spoon and set aside, and repeat with the remaining mushrooms, adding the additional 2 tbsp of olive oil per batch. set mushrooms aside. taste and correct for salt., in a large saucier or pot set over medium heat, add the butter, the 1 tbsp olive oil, and the finely chopped shallots. cook and stir until the shallots are softened, 3-4 minutes (do not brown)., add the rice. stir until all of the rice grains are coated in the fat and have become translucent around the edges, about a minute., crank the heat to high and immediately add 1/2 cup of the simmering broth. stir the rice, making sure you get into the corners of your pot with your spoon, so the rice doesn tsp stick. continue stirring until most of the liquid has been absorbed by the rice. add another 1/2 cup of broth and keep stirring., continue adding the broth , 1/2 cup at a time, adding more only when the last 1/2 cup has been absorbed, until rice is al dente. (depending on the rice, you may use all of the liquid, or you may have some liquid left over. or you may need to add additional rice. keep an eye on the rice, tasting a grain at a time if you need to, to determine when the rice is done.), stir in about three-quarters of the reserved sauteed mushrooms. add the 1/3 cup parmigiano , and the remaining 1 tbsp butter. taste and correct for salt., serve: spoon risotto into a bowl. top with some of the remaining sauteed mushrooms, a sprinkle of chopped parsley, and a few grindings of black pepper. serve with additional grated cheese on the side.