Instant Pot Spaghetti

Name: Instant Pot Spaghetti
Prep time: 10 min
Cook time: 15 min
Ingredients: 1 tablespoon olive oil (or avocado oil); 1 medium sweet onion (finely diced); 2 pounds brown mushrooms (thinly sliced (use a mandoline to work faster)); 6-8 garlic cloves (minced); 1 teaspoon Italian seasoning; Kosher salt and pepper (to taste); 29 ounces marinara sauce (2 x 14.5oz Jar ); 4 cups stock (beef, chicken or vegetable); 1 pound gluten-free or whole wheat spaghetti; 1 cup shredded Parmesan cheese; freshly chopped parsley or chili flakes ( to taste)

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This Instant Pot Spaghetti recipe is a favorite healthy meal for busy weeknights, with the sauce and pasta cooked together right in the Instant Pot. This vegetarian meal is full of rich flavor with mushrooms, Parmesan cheese, and a fresh sprinkling of chopped parsley.

A white bowl with Instant Pot Spaghetti garnished with Parmesan cheese

When you don’t want to have a ton of dishes to wash up, a one-pot pasta dish like this is a tasty hack for getting dinner on the table quickly. The pasta absorbs the flavors from the marinara and stock as it cooks, thickening the sauce and creating a flavor-packed, restaurant-quality meal. The high-pressure environment in the instant pot means that the pasta and sauce take mere minutes to cook, but tastes like a luxuriously slow-cooked marinara.

If you’re looking for more ways to use your Instant Pot to make richly flavored meals in minutes, try my Instant Pot Chilli Recipe or my Instant Pot Chicken Curry.

Recipe Overview

Skill Level

Beginner

Prep Time

10 mins

Cook Time

15 mins

Before You Get Started

To keep the dish vegetarian, opt for using vegetable stock in the sauce. You can stick with Parmesan, if it suits your dietary requirements, or choose a vegetarian Italian-style hard cheese instead.
To prevent the spaghetti from clumping as it cooks, it’s important to layer it in a criss-cross pattern in the Instant Pot. See the photos in the recipe card for guidance.
Don’t stir the dry spaghetti once it’s in the pot. You just need to push it down into the broth and marinara sauce to submerge it so that the noodles can fully absorb the liquid and cook evenly.
When manually releasing the steam by opening the valve on the Instant Pot, it’s really important to do this carefully, as hot steam will come out of the vent. I like to use a wooden spoon to turn the valve to the ‘open’ position so that my hands aren’t near the steam.
Once the pasta and sauce are cooked, give them a good stir to help the ingredients evenly distribute throughout.

Common Questions

Why did my spaghetti clump?

If you place the spaghetti into the Instant Pot in one big bundle, it’s likely to clump as it cooks. That’s why I recommend layering it in a criss-cross pattern which separates the noodles. You may find that a few noodles have stuck together during cooking so stirring the cooked pasta into the sauce at the end of the recipe helps to break up any small clumps.

How long does it take to cook spaghetti in the instant pot?

In this recipe, the spaghetti is cooked on MANUAL mode for just 3 minutes.

How much water is needed to cook spaghetti in the Instant pot?

For 1 pound of spaghetti, I use 19 ounces (two 14.5-ounce jars) of marinara sauce plus 4 cups of stock. This ratio strikes the right balance to ensure the pasta cooks through while producing a sauce that isn’t watery.

Can I make this vegan?

Yes! This recipe is already meat-free, so all you have to do is use a vegetable stock in the sauce and replace the Parmesan with a vegan alternative, or use a sprinkling of nutritional yeast instead.

Ingredients Needed

Below are the ingredients needed to make this Instant Pot Spaghetti. The full quantities are listed in the recipe card further down the post in the recipe card.

Ingredients to make spaghetti in an Instant Pot.

Olive oil: You can use light olive oil or avocado oil here if you prefer. You only need a small quantity for sauteing the vegetables at the start of the recipe.
Sweet onion: This adds an extra layer of complexity to the store-bought marinara and brings a bit of sweetness, too. You can also use a cooking onion.
Brown mushrooms: These infuse the sauce with an umami richness and add a lovely texture to the finished sauce.
Garlic cloves: I like to use fresh garlic here for the best flavor.
Seasonings: Italian seasoning, Kosher salt, and pepper
Marinara sauce: Use your favorite store-bought marinara here. I like to use ones with simple ingredients and no added sugar to ensure that the sauce is well-balanced.
Stock: You can use vegetable, chicken, or beef stock here – just choose whichever suits your dietary needs or taste preferences the most.
Spaghetti: Whole wheat spaghetti works really well here, but if you’re celiac, you can also use gluten-free spaghetti.
Parmesan cheese: It’s best to use freshly grated Parmesan cheese as it has the best flavor and will melt into the sauce nicely.
Fresh parsley and chili flakes: These are both optional extras you can add, to taste, to the finished dish. The parsley brings a vibrant freshness, and the chili flakes can round out the pasta with a nice kick, if that’s something you crave!

How to Make Instant Pot Spaghetti

process shot to saute the onion and mushroom in an Instant Pot.

1️⃣ Saute the vegetables

Set the Instant Pot mode to SAUTE. Cook the onions until softened, followed by the mushrooms. Stir in the garlic, Italian seasoning, salt, and pepper, and cook for a minute more.

✏️ Keep an eye on the veggies as they cook, stirring often, to prevent them from scorching on the bottom of the pot.

process shot of adding the marinara and the spaghetti into the Instant Pot.

2️⃣ Add the liquids

Stir in the marinara and the stock.

3️⃣ Add the spaghetti

Break the spaghetti noodles in half and lay them in a criss-cross pattern in the pot. Push them down to submerge in the sauce.

✏️ Layering the spaghetti in this fashion will prevent it from clumping as it cooks.

4️⃣ Place the lid on and pressure cook

Secure the lid and twist the venting valve to be sealed. Set the mode on the Instant Pot to MANUAL. Set the timer for 3 minutes.

process shot of cooking off the spaghetti and serving it in a bowl

5️⃣ Manually release the steam

Once the time is up, manually release the steam by opening the venting valve.

✏️ Be careful when you turn the valve as hot steam will come out of it. I like to use a wooden spoon to turn the valve to the ‘open’ position to ensure I don’t burn my hand!

6️⃣ Stir and finish

Stir the pasta for 1 minute to mix the sauce into the spaghetti. Stir in the Parmesan cheese, parsley and chili flakes, if using.

Variations & Substitutions

→ Add some meat: Sauté ground beef or turkey in the instant pot along with the veggies until no longer pink. It’ll infuse the sauce with even more flavor and add some bonus protein to the dish.

→ Change up the vegetables: You can use diced zucchini in place of the mushrooms for a summery twist on this dish.

→ Make it vegan: Use a vegan vegetable stock in the sauce and replace the Parmesan cheese with your favorite vegan alternative, or even a generous few pinches of nutritional yeast.

Storage & Make Ahead Tips

You can store the leftovers in an airtight container in the fridge for up to 3 days. To reheat, microwave on HIGH in a microwave-safe bowl for 2-3 minutes until piping hot.

Instant Pot Spaghetti

Before You Get Started

Common Questions

Ingredients Needed