Dried mushrooms are rehydrated in hot water, while lettuce and fennel are gently cooked in melted butter in a large, sturdy pot and then set aside. Onions take their place in the pot, followed by adding short-grain Arborio rice and hot water. This marks the beginning of the classic risotto-making ritual, where the cook stirs diligently and patiently.(I attempted making this dish using the mushroom stock, but it resulted in a too muddy and dank flavor.) The finely diced rehydrated mushrooms are introduced into the pot, along with a bit more water, and more stirring ensues. Finally, towards the end, the cooked lettuce and fennel, some Parmesan cheese, a generous sprinkling of nutmeg, and any remaining butter are added to the mix. The result is truly remarkable, especially in terms of the lettuce, which imparts a delicate mineral note above the velvety richness of the rice, reminiscent of a forest floor. —Sam Sifton
Place the dried mushrooms in a bowl and pour hot water. Allow them to steep for 20 minutes, squeeze out excess liquid, and finely chop the mushrooms. Set aside the mushroom broth for future use.
Bring four cups of water to a boil over high heat in a saucepan. Keep the water hot.
In a heavy saucepan, melt 5 tablespoons of butter over medium heat. Once it starts foaming, add the lettuce and fennel, cooking until they become tender. Remove them from the pan and set them aside. Add a tablespoon of butter and sauté the onion until it turns translucent. Add the Arborio rice and stir until it becomes glossy and heated.
Add a cup of hot water to the mixture and stir until the liquid is absorbed, which should take approximately 5 minutes. Add another cup of hot water and continue stirring until it's absorbed. Introduce the chopped mushrooms, a pinch of salt, and another half cup of hot water. Once the liquid has been absorbed, taste the rice to check if it offers a slight resistance when bitten. If it's too soft, add the remaining water and stir to combine.
Incorporate the cooked lettuce, fennel, Parmesan cheese, and any remaining butter. Finish by grating a generous amount of nutmeg over the mixture.