Add the spaghetti, garlic, vegetable broth, soy milk, nutritional yeast, salt, and a few grinds of black pepper to a large skillet or sauté pan. Cover and bring to a gentle simmer over medium heat.
After about 5 minutes, uncover and give the pasta a good stir to separate the noodles. Cover again and cook for another 3 minutes.
Remove the lid and continue cooking, stirring frequently, until the pasta is al dente and most of the liquid has been absorbed, forming a creamy sauce that coats the noodles.
Finish with the lemon juice and fresh parsley. Taste and adjust with additional salt and pepper as desired. Serve immediately.
