Portobello Mushroom and Barley Soup

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This Portobello and Barley Soup is a lovely, hearty, healthier option, featuring tender mushrooms, barley, and lots of veggies in a rich, flavorful broth.

Close up picture of a bowl of pressure cooker portobello and barley soup topped with fresh ground pepper and parsley, with buttered bread and a second bowl of soup in the background.

Why you’ll love making Portobello Barley Soup in an Instant Pot

This from-scratch Instant Pot soup tastes like it has simmered on the stovetop all day, but it’s mostly hands-off cook time.

This mushroom barley soup is a meatless twist on a classic beef and barley soup—but with more fiber and less fat and calories.

(Plus, a package of portobello mushrooms are about half as much as a pound of beef where I live.)

If you’re not a mushroom lover, don’t fret! I usually just tolerate mushrooms, but I enjoyed this soup. There are so many other flavors with the broth and the barley that the portobellos blend in well. 

If you love mushrooms, you have to try our other mushroom recipes that you can make in an Instant Pot: Beef Stroganoff, Coq au Vin, Deer Valley Beef and Wild Mushroom Stew, Chicken Marsala, and Chicken and Mushrooms.

Updated for 2025. We first featured this soup in 2013, and we’ve adapted it over the years as we got flavor suggestions from our readers that we really loved. We’ve updated this post with new pictures, updated instructions, and tips to help you get this recipe just right.

Ingredients for making Instant Pot portobello and barley soup, including vegetable broth, diced tomatoes, soy sauce, garlic, celery, carrots, tomato paste, salt and pepper, onions, portobello mushrooms, and pearled barley.

INGREDIENTS YOU NEED

Despite the longer ingredient list, this soup pretty much just calls for basic veggies and seasonings for the broth, plus barley and mushrooms: 

  • Avocado oil: Can sub canola or olive oil if you prefer.
  • Onion, celery, carrots: This classic mix, known as a mirepoix, is the essential flavor base for soups.
  • Vegetable stock: Can substitute beef broth if desired. 
  • Soy sauce: This adds a lot of umami without making the soup taste like soy sauce. I don’t recommend skipping it. 
  • Portobello mushrooms: We just bought them in a two-pack at the store. Make sure you look for a firm cap and stem.
  • Pearled barley: Pearled barley has had its husk and bran layer removed so it cooks up quicker than traditional hulled barley. Pearled barley has just under 4 grams of protein per cup, plus another 6 grams of dietary fiber.
  • Diced tomatoes and tomato paste: These add a lovely hearty flavor to the soup, and the tomato paste gives you more tomato flavor without the liquid that comes with diced tomatoes.
  • Fresh thyme: I like to make a little cheesecloth sachet to make the thyme easier to remove. However, you can add the herb directly to the cooking pot; just make sure to take extra care to fish all the parts out of it as you go.
  • Dried parsley: You can use fresh if you prefer. We love the look that dried parsley gives the finished dish.
  • Salt and pepper to taste: We generally test our recipes with Swanson’s Reduced-Sodium broth. When we switch to another brand, we find that our seasonings generally need to be adjusted to our tastes.

How to Make Portobello Mushroom and Barley Soup in an Instant Pot

This easy recipe will work in any brand of electric pressure cooker, including the Instant Pot, Ninja Foodi, or Power Pressure Cooker XL.

We like to start off the soup by sauteing the veggies in a little oil to really bring out the flavor of the veggies. However, if you’re in a hurry you can skip this step. 

Next, add the vegetable stock, water, soy sauce, salt, pepper, chopped mushrooms and barley and stir so they’re well mixed. 

Then add the diced tomatoes, tomato paste, thyme and parsley on top. Cook at High Pressure with a 25 minute cook time, then allow a natural pressure release for 10 minutes.

Remove the lid, adjust the seasonings, and serve with a nice crusty bread.

Overhead picture scooping out portobello and barley soup using a ladle from an Instant Pot, with fresh parsley in the background.

Important Tips for Making Barley Soup in an Instant Pot

To Prepare the Portobello Mushrooms

If you’re not used to preparing portobello, we trust Serious Eats’ mushroom cleaning and prep tutorial. We like to wash them in a bit of water to ensure they’re clean before we chop them.

Also, if you want to take the time, you can use the tip of a spoon to scrape off the dark “gills” on the underside of the portobello. This helps them appear less mushroom-y and helps avoid any off-taste. (It doesn’t have to be perfect—in the photo above you can see we definitely didn’t get all the gills.)

Adjusting the Liquids in the Soup

Note that the barley will continue absorbing liquid as it cools. (Like, there’s a noticeable difference from when we first served the soup and when we went back for seconds.) If the soup is a bit too thin for your liking, just wait 5–10 minutes before serving. 

And if you’re reheating your soup, you may need another can of broth or cup of water to bring it back to the original consistency.

An overhead picture of Instant Pot portobello and barley soup, topped with fresh parsley, and freshly buttered bread in the background.

Frequently Asked Questions about Making Portobello Barley Soup

Can I add ground beef to this meal? 

Absolutely! I’d recommend using 85% lean ground beef, since it holds up to the longer cook time.

Use a tablespoon of oil to saute the beef until it starts to brown, then remove to a plate lined with paper towels. Then saute the veggies. Then return the beef to the pot at the same time you add the barley, before you add the tomatoes. No change to the cook time.

In addition, I’d swap to beef broth for more beefy flavor. 

Can I use other mushrooms?

We haven’t tested it, but we’d try substituting cremini (aka Baby Bellas). Cremini are the same type of mushroom as portobello, just picked at an earlier stage. As a bonus, the store by us sells these already rough chopped and cheaper than a regular portobello.

However, if you want to minimize the mushroom flavor, white button mushrooms (another younger portobello variant) are supposed to be the least mushroom-y tasting mushroom.

How should I store leftovers?

Store leftover soup in an airtight container in the fridge for up to 4 days. Reheat on the stove, with the pot-in-pot method for 1 minute, or in the microwave. 

You can freeze this soup, just be aware that the barley will have a different texture when you thaw it. (The barley tends to break down if you cook it in the microwave; however, if you thaw it overnight in the fridge first, it heats up better.)

A large bowl of portobello mushroom and barley soup in a white bowl, with buttered bread and another bowl of soup, and an Instant Pot in the background.

More Hearty Instant Pot Soup Recipes

Try some of our other warm and cozy Instant Pot soup recipes in your pressure cooker next:

  • Vegetable Beef Soup: This one is great beefy alternative to our Portobella Mushroom soup—featuring lean ground beef, tomatoes, potatoes, carrots, peas, and rice.
  • Ribollita uses a surprising ingredient as a thickener—bread! The bread breaks down and creates a creamy consistency without using a drop of heavy cream!
  • French Onion Soup: We love making French Onion Soup in our pressure cooker because the pressure cook setting speeds up cooking the onions. Then, once the onions are caramelized, we use a second pressure cook to flavor the beef broth.
  • Buffalo Chicken Soup: Our friend Kalyn created this easy Instant Pot soup recipe, which features the same flavors you’ll find in Buffalo chicken wings.      

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A fresh bowl of Instant Pot mushroom and barley soup topped with fresh parsley, with buttered bread in the background.

Instant Pot Portobello and Barley Soup

Servings: 6 people
Prep Time: 20 minutes
Cook Time: 25 minutes
Additional time: 25 minutes
Total Time: 1 hour 10 minutes
Course: Soup
Cuisine: American
This easy, meatless soup features tender portobello mushrooms, barley, and classic vegetables in a tomato-based broth.
5 from 2 votes
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Ingredients

  • 1 tablespoon avocado oil or canola oil
  • 1 cup yellow onion finely diced
  • 2 cloves garlic minced
  • 2 carrots diced
  • 3 celery stalks diced
  • 4 cups vegetable stock plus more as needed
  • 1 cup water
  • 1 teaspoon soy sauce
  • 2 teaspoons salt
  • 1 teaspoon pepper
  • 2 large portobello mushrooms about 6 oz, roughly chopped
  • 1 cup pearled barley well-rinsed and drained
  • 1 can (14.5 oz) petite diced tomatoes
  • 1 tablespoon tomato paste
  • 2 thyme sprigs wrapped in a cheesecloth sachet if desired
  • 1 tablespoon dried parsley
  • Salt and pepper to taste

Instructions

  • Select saute and preheat the pressure cooking pot. When hot, add the oil and saute the onion, carrots, and celery, and saute until softened, about 5 minutes. Add the garlic and saute 1 minute more.
  • Add the vegetable stock, water, soy sauce, salt, pepper, mushrooms, and barley, and stir to combine. Add the petite diced tomatoes, tomato paste, thyme, and parsley. Lock the lid in place. Select High Pressure and 25 minutes cook time. Allow the pressure to release naturally for 10 minutes, then finish with a quick pressure release.
  • When the valve drops, remove the lid. Taste the soup and adjust the seasoning with salt and pepper if needed.
  • Serve immediately.

Notes

The barley will absorb more broth as it cools, so you may prefer adding another cup of broth or water after pressure cooking to reach desired consistency.
Adapted from JL Goes Vegan

Nutrition

Calories: 200kcal | Carbohydrates: 40g | Protein: 6g | Fat: 3g | Saturated Fat: 0.4g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 2g | Trans Fat: 0.002g | Sodium: 1595mg | Potassium: 554mg | Fiber: 8g | Sugar: 8g | Vitamin A: 3960IU | Vitamin C: 11mg | Calcium: 59mg | Iron: 2mg

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