In a large pot, add the pasta, sliced mushrooms, garlic, half of the pesto, olive oil, salt, Better-than-Bouillon, and water.
Bring to a boil and then reduce to a simmer. Cook for 10-11 minutes or until the pasta is al dente. Make sure to stir during cooking time so that the pasta cooks evenly.
Add the rest of the pesto and vegan margarine. Stir and serve.