Bring a large pot of water to a boil with 1 tablespoon of the olive oil and a pinch of salt. Cook the pasta according to the instructions on the package until al dente, and drain thoroughly. 

While the pasta is cooking, in a large skillet over medium heat, warm 3 tablespoons of the olive oil and sauté the mushrooms with the soy sauce and thyme for about 5 minutes, until the mushrooms are tender. Transfer to a large bowl.

In the same skillet, heat the remaining 1 tablespoon of olive oil over medium heat and sauté the onion and garlic for about 5 minutes, until soft and translucent. Allow to cool slightly.

To make the sauce, throw the onion mixture, 1 1/2 teaspoons of salt, the broth, lemon juice, cashews, cauliflower, nutritional yeast, miso paste, turmeric, and cayenne pepper into your blender, and blast on high for 30 to 60 seconds, until smooth and creamy.

Transfer the pasta to a large pot, and stir in the remaining 1 tablespoon of olive oil. Stir the sauce into the pasta along with the mushrooms and gently warm over low heat. Stir in the parsley, chives, and green onions. Add salt and pepper to taste.