Cook the pasta according to package instructions until al dente. Drain and set aside.
In a large skillet, heat the olive oil over medium heat. Add the sliced onion and salt, cooking for about 10 minutes until the onions are soft and translucent.
Sprinkle the sugar over the onions and continue to cook for another 10-15 minutes, stirring occasionally, until the onions are caramelized and golden brown.
Add the minced garlic and cook for an additional 1-2 minutes until fragrant.
Pour in the vegetable broth, almond milk, nutritional yeast, soy sauce, onion powder, garlic powder, and black pepper. Stir to combine.
Bring the mixture to a simmer, then add the cornstarch mixture to thicken the sauce. Stir continuously until the sauce thickens, about 2-3 minutes.
Add the cooked pasta to the skillet, tossing to coat the pasta evenly with the sauce. Cook for another 2-3 minutes to heat through.
Serve immediately, garnished with fresh parsley.