In a large pot of boiling salted water, cook pasta until al dente; drain, and return to pot. Set aside. While pasta is cooking, in a small bowl, soak porcini in 1 1/2 cups hot water until tender, at least 15 minutes.
Meanwhile, melt 1 tablespoon butter in a large skillet over medium heat. Add shallot; season with salt and pepper. Cook, stirring occasionally, until shallot begins to soften, 3 to 4 minutes. Add wine; cook until almost evaporated, 3 to 5 minutes.
Add button and shiitake mushrooms. Cook over medium-high heat, stirring occasionally, until mushrooms are tender and begin to brown, 6 to 8 minutes.
Add porcini and their soaking liquid (leaving any grit at the bottom of the bowl) and thyme to skillet. Cook, stirring occasionally, until liquid reduces by half, 2 to 4 minutes. Transfer porcini mixture to pot with pasta. Add Parmesan and remaining butter, and toss to combine. Season with salt and pepper, and serve with more Parmesan.
Soaking dried porcini mushrooms in hot water softens them and creates an intense broth used for the pasta's sauce. Find dried porcini in the international aisle of markets and gourmet stores.
Yummy recipe if you like mushrooms. I added some lemon zest at the end (a trick I recently learned from one of my favorite restaurants). It took it to a whole new level. Next time, I'm going to see if sour cream adds to it as well.
This dish is delicious, and it's really simple to prepare. It's also much more subtle in flavor than I expected it to be. Sometimes mushrooms can be overwhelming, but this was lovely.
This pasta dish is AWESOME.