Bring salted water to a boil in a large pot. Add penne pasta and boil according to package directions or until pasta is aldente.
In the meantime, heat oil in a large saucepan over medium-high heat. Add onion and cook until soft, about 3 minutes.
Stir in garlic and spinach and cook until spinach has wilted about 1 minute.
Add tomato, Italian seasoning, and pepper.
Add cashew cream, nutritional yeast, and salt.
Drain pasta using a colander, (reserving a little of the pasta water to thin the sauce) and add pasta to the saucepan, stir to coat. Check seasonings and serve.