Cook the pasta: In a large pot of boiling salted water, cook the pasta noodles according to package instructions. Drain well and set aside.
Make the Cashew Cream: Bring 3 cups of water to a boil. Pour the hot water over the cashews and let soak for 5 minutes. Drain the cashews and discard the soaking water. Add them to a blender along with the 3/4 cup fresh water and apple cider vinegar. Blend until very smooth. Set aside.
In a large pot or pan, warm the olive oil over medium-high heat. Add the onions and mushrooms. Stir frequently until the onions and mushrooms are tender and have shrunk in size. Season with a little salt + pepper.
Stir in the garlic and cook for 1 more minute, then add the white wine and deglaze the pan by scraping any brown bits from the bottom of the pan. Sprinkle the flour on top and stir it into the vegetables. Gradually pour in the vegetable broth, stirring constantly. Now add the dijon, nutritional yeast, thyme and salt. Bring to a boil, then lower the heat and simmer for 4-5 minutes until it thickens slightly.
Now add the cashew cream and stir it in. You should have a very creamy mushroom gravy at this point. Stir in the cooked pasta and cook until heated throughout, about 1-2 minutes. Taste, add additional salt and pepper, as desired. Garnish with fresh parsley or more thyme.