1. Soak dried mushrooms for 20-30 minutes in the warm water. While they are soaking, dice and fry the bacon, if you’re using it. When it’s crispy, remove it from the pan onto a paper towel-lined plate to drain.
2. Chop the onion, garlic, and sage.
3. Remove the soaking mushrooms from the liquid and squeeze them out–but save the soaking liquid! Chop the soaked mushrooms up nice and fine.
4. Put the pasta water on to boil, and salt it liberally. When it’s boiling, add your pasta and cook according to package directions.
5. Heat the oil and butter together over medium-high until the butter is melted. Add the onion and diced (previously dried) mushrooms, and cook for about 8 minutes.
6. Add the garlic, fresh mushrooms, and sage. Salt generously, and sprinkle in black pepper as well. It’s important to season well at this stage so that the button mushrooms absorb some flavor and release their liquid. Cook for about 5 minutes, stirring occasionally.
7. Then add the wine and the soaking liquid from the dried mushrooms. Turn the heat to medium-low and simmer gently for 5 minutes. Your pasta should be cooking away by now. Check in on it every now and then.
8. Turn the heat on the mushrooms to low, and stir in both the mascarpone and the gorgonzola. Taste and re-season. My sauce is usually a little thin at this point, so mix the cornstarch and water together into a slurry and add this into the pot to thicken it.
9. Drain the pasta when it’s done, and add it directly into the mushroom sauce. If you’re using bacon, this is the time to add it in. Stir until it’s incorporated, and serve! Garnish with whole sage leaves or some more chopped sage.