Cook the pasta in a large pot of boiling water until quite al dente (it will finish cooking in the sauce).
While the pasta is cooking, melt the butter in a large frying pan on medium heat.
Add the shallots and cook until transparent (about 3-4 minutes). Add the garlic and cook another minute.
add the mushrooms and sauté until the mushrooms are fully cooked.
Stir in the cream and parsley, lower the heat, and simmer gently until thickened (1-2 minutes).
Reserve some of the pasta water and drain the pasta .
Add the pasta to the sauce and toss to coat, adding the reserved water as needed to loosen the sauce.
Serve immediately with grated cheese.
Video
Notes
To clean the mushrooms, use damp paper towels to remove any dirt. Cleaning mushrooms with water cause them to become waterlogged. Mushrooms absorb water like sponges and won't brown well when cooked if they are full of water.
If you want to use water, you can quickly rinse the mushrooms and pat them dry with paper towels, but don't soak them.
When cooking mushrooms, don't overcrowd the pan. Cook mushrooms in a pan with a good amount of surface area. You want to be able to spread the mushrooms in a single layer to allow contact with the hot pan and let moisture evaporate quickly, so they brown nicely.
To add an even deeper mushroom flavor, add some dried porcini mushrooms (that have been soaked, of course) and add a bit of the liquid you use for soaking them. Since I wanted a quick and simple dish, I used only fresh mushrooms.