Soak the sun dried tomatoes in soy sauce.
Sauté onion and garlic on a bit of oil. Keep adding splashes of water if needed.
After 3-4 min add the milk, nutritional yeast, salt and pepper.
Cook for about 7 min and then add the sun-dried tomatoes.
Continue cooking all together for another few min. You want the sauce to become a bit thicker. So cook longer if needed. You can also add a bit of flour before adding the milk.
Cook the spaghetti separately. I like to cook them al dente and then cook them 2-3 min more in the sauce.