Bring a large pot of water to a boil.
Cook pasta according to package instructions. When the pasta is al dente and about 2 minutes from done add the frozen vegetables. Pop the lid back on and let it come up to a quick boil to cook the vegetables. Remove from heat, drain, and set aside.
While the pasta is draining, put the pot back on the stove and add the butter.
Once butter is melted, add the minced garlic and stir quickly. Add the tomato paste, nutritional yeast, salt, and onion salt. Stir well—it will be thick.
Slowly whisk in the milk until well incorporated.
Add the vegetable and pasta mix into the pot and stir well to coat.
Serve right away, or pack up for school lunches!