Easy One-pot Vegetarian Spaghetti (Ready in 25 Minutes)

Vegetarian spaghetti with mushrooms and spinach makes an easy, healthy one-pot pasta dinner that’s ready in 25 minutes!


  • 2 teaspoons extra-virgin olive oil
  • 1/2 medium yellow onion, chopped
  • 1 (8 oz.) package button mushrooms, sliced
  • 2 cloves garlic, minced
  • 1/2 teaspoon salt
  • 1/4 teaspoon black pepper
  • 1/4 teaspoon red pepper flakes (optional)
  • 2 cups low-sodium vegetable broth
  • 1 (14.5 oz.) can fire-roasted diced tomatoes
  • 10 oz. thin spaghetti noodles (I use whole wheat)
  • 3 cups fresh spinach or baby spinach
  • 1/4 cup grated Parmesan or Italian-style hard cheese, plus extra for serving
  • For serving: 1/4 cup fresh chopped basil or parsley (optional)


  1. 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.
  2. Add garlic and season with salt, pepper and red pepper flakes (if using) and saute another 30 seconds.
  3. Increase heat to high then add canned tomatoes and vegetable broth. Bring to a boil.
  4. 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.)
  5. Remove lid and add fresh spinach, a couple of handfuls at a time, stirring to get the spinach mixed in and wilted.
  6. Remove from heat and let spaghetti sit, covered, for a few minutes
  7. Stir in Parmesan cheese, taste and adjust seasonings.
  8. 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 sauté everything together until it’s slightly tender.
  • Parmesan cheese may not be considered strictly vegetarian (see the post above for details), so you can substitute an Italian-style hard cheese here. Or if you want to make this recipe vegan, 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 or to serve both vegetarians and non-vegetarians.
  • You can also stir in 1-2 cups of mozzarella cheese if you want a super cheesy pasta.