One-Pot Vegetarian Lasagna Soup

This One-Pot Vegetarian Lasagna Soup delivers all the cozy, cheesy comfort of classic lasagna in a fraction of the time, no layering required.

Broken lasagna noodles swim in a rich tomato broth with mushrooms and a dollop of creamy ricotta on top. It’s the kind of meal that feels like a slow-cooked Sunday dinner but comes together on a busy Tuesday night.

Why This One-Pot Soup Hits the Spot

The broken noodles release starch as they simmer, turning the broth naturally creamy without any cream. It’s a trick from one-pot pastas that works beautifully here.

I love that the whole thing happens in one pot. Sauté, simmer, serve—no colanders, no layering, just a deep pot and a spoon.

Ingredients

• 2 tbsp olive oil: for sautéing the vegetables
• 1 medium onion, diced: yellow or white both work
• 3 cloves garlic, minced: fresh garlic, not jarred, gives the best kick
• 8 oz cremini mushrooms, sliced: add meaty texture; portobello or white mushrooms are fine
• 1 small zucchini, diced: optional, but adds substance and uses up summer squash
• 1 tsp dried oregano
• 1 tsp dried basil
• Pinch of red pepper flakes: optional, for gentle heat
• 1 (28 oz) can crushed tomatoes
• 4 cups vegetable broth: low-sodium so you can control the salt
• 8 oz lasagna noodles, broken into 2-inch pieces: regular curly noodles work best
• 1 cup ricotta cheese: part-skim or whole milk, for dolloping
• 1/2 cup shredded mozzarella: for melting on top
• Salt and black pepper

Variations / Substitutions

• Dairy-free/vegan: use cashew ricotta and skip the mozzarella or use your favorite plant-based shreds.
• Gluten-free: use gluten-free lasagna noodles, but they cook quickly so check them early.
• Add more protein: stir in a drained can of white beans or chickpeas with the broth.
• Extra greens: toss in a handful of baby spinach at the end and stir until just wilted.
• More spice: double the red pepper flakes or add a pinch of cayenne.

Hearty Vegetarian Eggplant Lasagna is a great main dish to serve alongside this soup.

How to Make One-Pot Vegetarian Lasagna Soup

Step 1: Sauté the Veggies

Heat the 2 tbsp olive oil in a large pot over medium heat. Add the diced onion and a pinch of salt and cook for about 5 minutes, until softened and translucent. Add the garlic and cook 1 minute more, just until fragrant. Toss in the sliced mushrooms and diced zucchini, season with another pinch of salt, and cook 7 to 8 minutes, until the mushrooms have released their liquid and started to brown and the zucchini is tender.

The kitchen will smell like onions and garlic, and the mushrooms will shrink and turn golden, which builds the savory base of the soup. Don’t rush this step; a little color adds deep flavor.

Step 2: Build the Broth

Pour in the crushed tomatoes and 4 cups vegetable broth. Add the dried oregano, dried basil, and a pinch of red pepper flakes if using. Stir everything together and bring the liquid to a boil over high heat, which should take 3 to 5 minutes. Once boiling, reduce the heat to medium-low to keep a steady simmer.

The broth will look deep red and smell herbaceous. This is the lasagna soup base, and it already tastes rich even before the pasta goes in.

Step 3: Simmer the Noodles

Add the broken lasagna noodles directly into the simmering broth and stir to submerge them. Cook uncovered for 10 to 12 minutes, stirring now and then so the noodles don’t stick to the bottom. If the soup gets too thick before the noodles are tender, add a splash of extra broth or water. Taste and adjust salt and pepper.

As the noodles cook, they’ll release starch and transform the liquid from a thin broth into a creamy, hearty stew. The pasta should be al dente, with a slight bite, not mushy.

Step 4: Ladle and Dollop

Ladle the hot soup into bowls. Top each serving with a generous spoonful of ricotta cheese and a scattering of shredded mozzarella. Fresh basil leaves or a crack of black pepper on top make it even better. Serve right away while the cheese melts into the soup.

Tips for the Best Lasagna Soup

• Let the mushrooms brown deeply.: A golden sear adds a savory, almost meaty depth that carries the whole pot. Don’t just sweat them; listen for the sizzle.
• Break the noodles into pieces about 2 inches wide.: Too small and they’ll turn to mush; too large and they’re awkward to eat in a spoon.
• If you plan on leftovers, cook the noodles separately: in a small pot of water and add them to each bowl. Otherwise they’ll soak up all the broth overnight.
• Don’t stir the ricotta into the pot.: Dollop it on top of each bowl so it stays creamy and melts as you eat.

Storing Leftover Lasagna Soup

Refrigerate leftovers in an airtight container for up to 4 days. Reheat gently on the stovetop over medium-low heat, adding a splash of broth or water because the noodles will have absorbed a lot of liquid overnight.

What to Serve With This Soup

Garlic bread is a natural choice—the buttery, crisp edges are perfect for dunking. For a lighter side, a simple arugula salad with lemon vinaigrette cuts through the richness of the tomato broth and cheese.

Frequently Asked Questions

Can I use no-boil lasagna noodles?

Yes, but reduce the simmering time to 5 to 7 minutes. No-boil noodles cook faster and can turn mushy more easily than regular noodles.

Can I make this in a slow cooker?

You can, but the pasta gets too soft if it sits for hours. Sauté the vegetables on the stovetop first, then transfer everything except the noodles to the slow cooker. Cook on low for 6 hours, add the broken noodles in the last 20 to 30 minutes on high, and serve as soon as the pasta is tender.

Can I freeze this soup?

I don’t recommend freezing it with the noodles already in the soup; they turn unpleasantly mushy when thawed. If you want to freeze a batch, make the soup base without the pasta, freeze that, and cook fresh noodles in the soup when you reheat it.

Vegetarian Lasagna Soup Recipe

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Prep Time 15 minutes mins

Cook Time 25 minutes mins

Total Time 40 minutes mins

Servings: 4 servings

Calories: 460

Ingredients Method Notes

Ingredients

  

• 2 tbsp olive oil
• 1 medium onion, diced
• 3 cloves garlic, minced
• 8 oz cremini mushrooms, sliced
• 1 small zucchini, diced
• 1 tsp dried oregano
• 1 tsp dried basil
• Pinch of red pepper flakes (optional)
• 1 (28 oz) can crushed tomatoes
• 4 cups vegetable broth
• 8 oz lasagna noodles, broken into 2-inch pieces
• 1 cup ricotta cheese
• 1/2 cup shredded mozzarella
• Salt and black pepper

Method

 

1. Heat olive oil in a large pot over medium heat. Cook onion with salt 5 minutes, then add garlic and cook 1 minute more. Add mushrooms and zucchini, season, and cook 7 to 8 minutes until browned.
2. Pour in crushed tomatoes and broth, add oregano, basil, and red pepper flakes. Bring to a boil, then reduce heat to a simmer.
3. Add broken lasagna noodles. Simmer uncovered 10 to 12 minutes, stirring occasionally, until noodles are tender. Thin with broth if needed and adjust seasoning.
4. Ladle soup into bowls, top with ricotta and mozzarella, and serve hot.

Notes

If you’d like a little extra richness, toss a Parmesan rind into the pot while the broth simmers; just fish it out before serving. The soup will thicken as it sits, so keep extra broth handy for reheating.