1/4 cup grated Parmesan cheese, plus extra for serving
For serving: 1/4 cup fresh chopped basil or parsley (optional)
Heat olive oil in a medium pot over medium heat. Add onion and mushrooms and saute for 5-7 minutes, until tender and the liquid from the mushrooms has been mostly cooked off.
Add garlic and season with salt, pepper and red pepper flakes (if using) and saute another 30 seconds.
Increase heat to high then add canned tomatoes and vegetable broth. Bring to a boil.
Add spaghetti noodles and stir until they wilt and fit in the pot. Cover the pot, reduce heat to medium-low and cook for 5 minutes. (Your liquid should be at a low boil this whole time.)
Remove lid and add fresh spinach, a couple of handfuls at a time, stirring to get the spinach mixed in and wilted.
Remove from heat and let spaghetti sit, covered, for a few minutes
Stir in Parmesan cheese, taste and adjust seasonings.
Serve with fresh basil or parsley and extra Parmesan cheese, if desired.
You can substitute cremini or portobello mushrooms for the regular button mushrooms if you prefer. And you can add any extra veggies you have on hand: peppers, zucchini and broccoli would all be great. Add them with the onions and mushrooms and saute everything together until it’s slightly tender.
Some Parmesan cheese may not be considered strictly vegetarian (see the post above for details), so you can substitute an Italian-style hard cheese here. If you want to make this recipe vegan, just substitute nutritional yeast or your favorite vegan cheese in place of the Parmesan.
Or if you’re not vegan or vegetarian, you can stir in some cooked, shredded chicken or rotisserie chicken with the spinach at the end to warm it through and make a more hearty meal.
You could also stir in 1-2 cups of mozzarella cheese if you want a super cheesy pasta.