Bring a large pot of water to a boil for the pasta.
Place the mushrooms in a small saucepan. Add enough stock to just cover, about 1 1/2 cups. Bring to a simmer over medium, reduce the heat to low, and keep warm until the mushrooms are reconstituted, 15 to 20 minutes. Using a slotted spoon, transfer the mushrooms to a work surface; chop. Reserve the mushroom soaking liquid.
Meanwhile, in a large skillet, heat the EVOO, three turns of the pan, over medium. Add the onion, garlic and thyme; season with salt and pepper. Cook, stirring often, until softened, 10 to 12 minutes. Add the tomato paste and stir until fragrant, about 1 minute. Stir in the wine; simmer until reduced by half, 3 to 5 minutes. Add the mushrooms and the reserved soaking liquid (avoid any grit that may have settled in the pan). Stir in the butter; reduce the heat to low.
Salt the boiling water and add the pasta. Cook, stirring often, until al dente. Add a ladle of starchy cooking water to the sauce, then drain the pasta.
Add lemon juice and parsley to the sauce, then the pasta and some cheese; toss to coat. Serve in shallow bowls and top with more cheese.