Soak raw cashews for or at least 1 hour (or overnight), drain and rinse them. Set aside.
Cook pasta in salted boiling water according to package instructions. When the pasta is finished cooking, reserve about 1/4 cup of the pasta water, and drain the rest.
While the pasta is cooking, add oil to a skillet over medium-high heat. Add the sliced mushrooms and saute for 4-5 minutes until they start to turn golden brown.
Add the thyme, salt, and pepper to the pan and stir for one additional minute.
Remove half of the sauted mushrooms from the pan and add to a high speed blender, along with the soaked cashews and almond milk. Blend for couple of minutes or until very creamy and smooth.
Add blended sauce to the pan with the remaining mushrooms. Stir.
Add the reserved pasta water for a thinner consistency, and taste and adjust seasonings as needed.
Let sauce simmer for about two minutes. Mix in cooked pasta.