Cover cashews with hot water, and let soak for about 30 minutes (by this time, the recipe should be almost done!)
Bring a large pot of water to a boil and cook the pasta according to package directions. Drain, and set aside.
In a large pot, heat the vegan margarine and add the onions/shallots, garlic, and mushrooms to the pan. Sauté on low for about 10 minutes, until the vegetables begin to soften. Add the white wine and thyme to the pot, and cook for an additional 5 minutes until most of the wine evaporates. Stir in the flour until mixture becomes thick, and add the almond milk.
In a blender, blend the cashews with their soaking water, and add the juice of one lemon. Blend on high for 1-2minutes until it becomes a cashew cream with a thick consistency.
Now everything comes together: To the pot with the mushrooms/almond milk sauce: add the cooked pasta, cashew cream, and (optional) stir in the vegan yogurt if using. Add parsley. Taste and adjust salt/pepper levels.