Blend the tofu, soy milk, yeast, miso paste, salt, pepper and nutmeg in a blender. Set aside.
Toast the pine nuts in a dry frying pan until golden brown. Set aside.
In the same frying pan, heat a bit of extra virgin olive oil or vegetable stock and sauté the mushrooms for a few minutes until browned a bit. Season to taste with salt and pepper and set aside.
Cook the pasta in lightly salted water according to instructions on the package. Drain well and mix with the sauce, mushrooms and pine nuts. Mix well and then throw in the spinach leaves. If the leaves are big, roughly tear them up before adding to the pasta. Toss to mix and serve immediately.