In a large pot of boiling salted water, cook pasta until al dente. Reserve 3/4 cup pasta water; drain pasta and return to pot.
Meanwhile, in a large skillet, melt 1 tablespoon butter over medium. Add onion and cook until softened, about 4 minutes. Add wine and cook until almost evaporated, 4 to 6 minutes. Add mushrooms; season with salt and pepper and cook until browned, about 8 minutes. Remove skillet from heat and stir in 1 tablespoon butter.
Add mushroom mixture, ricotta, and lemon juice to pasta; stir to combine, adding enough pasta water to create a thin sauce. Serve topped with Parmesan.
For even more flavor, experiment with dried porcini mushrooms.
This was awful. Please do not waste mushrooms or your time on this recipe.
This was pretty bland, not sure why. My husband's words were, "well, the flavours are nice, you just can't really taste them that often." Really, really subtle. I doubt I'd make it again, but if I did, I'd add shallots to the onions, maybe a little garlic at the end, a lot more lemon juice and wine and salt and pepper, and I'd grate the parm so it melted in throughout the dish, instead of being in big chunks in a few places.
This was delicious! I can't believe what a difference the fresh lemon juice made. I also added spinach for a little extra nutrition.