Heat the water in a pan. When it starts to boil, remove from stove and pour over the dried porcini in a bowl that can withstand the hot water. Let the porcini soak in the water for at least 30 minutes.
Place a sieve over a bowl and line it with a wet paper towel. Pour the mushrooms into the sieve. Reserve the porcini soaking water for another use. Rinse the mushrooms, then coarsely chop and set aside.
Heat the olive oil in a large skillet on medium heat. Add the shallots, cook for a few minutes until they begin to soften. Add the garlic, and cook for another minute.
Stir the about half of the button mushrooms into the skillet, along with the pinch of salt, and give them a couple of minutes to start cooking down. Add the rest of the button mushrooms.
Cook the button mushrooms on medium low heat for about 10 minutes, until they start to soften and “sweat”. Add the porcini mushrooms along with the sage and thyme. Cook for another 3 minutes, then add the red wine.
Cook the mushrooms until the red wine is mostly absorbed, about 5 minutes. Finish the dish by stirring in the truffle butter and adding black pepper and salt to taste. Serve immediately or cover to and keep warm until it is time to eat. Serve topped with optional grated cheese if desired.
Notes
This recipe provides a pretty good serving for 8 people or a small portion for 12. You could scale it up for a larger group by doubling the recipe. You could also just increase the porcini portion if you like.
The reserved liquid from soaking the porcini mushrooms can be used as stock in recipes such this Chicken and Mushroom Risotto recipe.