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Caramelized Onion and Mushroom Soup

5 from 5 votes

Thick, creamy, and filled with amazing depth of flavor, this Caramelized Onion and Mushroom Soup is a tasty combination of sweet, caramelized onions, umami-packed mushrooms, and more. Easy to make and loaded with flavor, if you love mushrooms and onions, you’re going to really love this soup!

Caramelized onion and mushroom soup in a white bowl with a second in the background.

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This is not the prettiest soup – I’m the first to admit that. However, ignore the color and grab a spoon because the flavor is going to knock your socks off! This is a gluten-free Caramelized Onion and Mushroom Soup with a creamy, silky texture and a rich flavor from the umami-packed ingredients.

It’s also a super simple soup to make and can be on the table in about 40 minutes. Don’t rush the onions because the more caramelized they are, the deeper the flavor your soup will have. Ready for flavor? Grab your ingredients, and let’s get cooking!

Horizontal top-down shot of two bowls of Caramelized Onion and Mushroom Soup.

What you’ll love about Caramelized Onion & MushrooM SOup


  • It’s silky smooth and so full of rich umami flavor!
  • It’s low in carbs, is naturally gluten-free, and can easily be made vegan.
  • It’s easy to make and freezes great!

Ingredients

  • Butter – I cook with salted butter. You can adjust the seasonings at the end of the cooking time.
  • Onions – Regular yellow cooking onions will do the trick.
  • Cremini mushrooms – You can use white mushrooms, too, but they won’t have quite the same depth of flavor.
  • Garlic – Fresh garlic plays so nicely with the onions and mushrooms!
  • White wine – Adds richness and acidity. You can skip the wine, but I really recommend it.
  • Beef broth – Use low or no sodium added broth to control the sugar.
  • Chicken broth – Homemade works best, but a good quality store-bought brand is also good.
  • Thyme – A few sprigs of fresh thyme are all the herbs you need.
  • Cream – Heavy whipping cream adds so much to this soup. It goes in at the very end of the cooking time.
  • Bacon or Pancetta – A tasty crunchy and salty topping, a bit of crumbled bacon or pancetta puts this soup over the top.
  • Salt and pepper – To season the soup. White pepper won’t add ugly black flecks in your soup.
Labeled ingredients to make Caramelized Onion & Mushroom Soup.

How To Make The Best Caramelized Onion & Mushroom Soup

  1. Melt the butter in a large skillet or soup pot and add the onions. Turn the heat down and cook the onions low and slow until they turn a caramel color. Stir often.
  2. Add the sliced mushrooms to the onions and cook until the mushrooms are softened.
  3. Add the garlic and cook an additional minute.
  4. Deglaze the pan with the white wine and simmer for a minute until the wine is mostly evaporated.
  5. Add the chicken and beef broth and sprigs of thyme. Simmer for about 10 minutes, covered.
  6. Pan-fry the bacon or pancetta until crisp, while the soup is simmering.
  7. Transfer the soup mixture to a blender – reserving about 1 cup of chunky onions and mushrooms – and puree the soup until it is thick and creamy.
  8. Pour the pureed soup back into the soup pot along with the reserved soup. Bring it back to a simmer, then turn off the heat.
  9. Add the cream to the soup, season with salt and pepper, and garnish with the crumbled bacon or pancetta before serving.
Caramelized onion and mushroom soup in a black bowl with spoons nearby.

Chef Jenn’s Tips

  • The hardest part about making this soup is waiting for the onions to caramelize. You can use about 1 cup of leftover caramelized onions, if you have them, or do this step ahead of time. Caramelized onions will keep for a few days in the fridge.
  • Cremini mushrooms are my pick for this recipe because of their deep mushroom flavor. If you use portobello mushrooms, be sure to remove the dark gills with a spoon before cooking, or they’ll discolor your soup.
  • Half chicken broth and half beef broth is an old chef trick for coaxing great flavor out of soups without it tasting all of beef or chicken. Try it!
  • Be careful when using the blender. Hot liquids like to explode when being blended. Remove the hole in the lid and cover the top of the blender with a clean kitchen towel. Start on low and work the speed up to high until the soup is pureed.

Recommended

Variations

  • This Caramelized Onion & Mushroom Soup is naturally gluten-free, but you can thicken it with a bit of flour and water slurry before you puree the soup. Mix 1 tablespoon of flour with 3 tablespoons of water until smooth and add to the soup in a drizzle while whisking. Simmer to thicken.
  • To make this a vegetarian or vegan Caramelized Onion & Mushroom Soup recipe, use vegetable broth in place of the beef and chicken, use olive oil instead of butter, and use your favorite dairy-free cream in place of the heavy whipping cream. Instead of a crispy bacon topping, use toasted nuts.
  • You don’t have to puree the soup. You can leave it chunky – it is still delicious.

Make It A Meal

Wondering what to serve with Caramelized Onion and Mushroom Soup? How about a tasty pastrami sandwich or French dip slider? I also love a bowl of pasta salad with this soup because it is naturally low in carbs.

Storage

This Caramelized Onion and Mushroom Soup Recipe will keep in an airtight container in the fridge for 3-4 days. If you want to keep it longer than that, pop it into the freezer.

Step By Step Process

Caramelized onion and mushroom soup in a black bowl with spoons nearby.
Print Pin
5 from 5 votes

Caramelized Onion & Mushroom Soup

Creamy, silky, and so delicious, this is an easy soup that's packed with umami-rich flavor and ingredients. Perfect on a cold day or whenever you're craving a great bowl of soup, pair this soup with a salad, sandwich, or a chunk of crusty bread.
Course Soups & Stews
Cuisine American
Keyword caramelized onion and mushroom soup, caramelized onions, cremini mushrooms, mushroom soup, mushrooms, onion soup
Prep Time 30 minutes
Cook Time 15 minutes
Total Time 45 minutes
Servings 6 servings
Calories 222kcal
Author Chef Jenn

Equipment

Ingredients

  • 2 tablespoons butter
  • 3 cups sliced onions
  • 1 pound cremini mushrooms
  • 2 cloves garlic chopped
  • 1/4 cup white wine chardonnay is great in soups
  • 4 cups low sodium beef broth
  • 2 cups low sodium chicken broth
  • 3 sprigs fresh thyme or 1/2 teaspoon dried thyme
  • 4 slices bacon or 1/4 pound pancetta
  • 3/4 cup heavy whipping cream
  • salt and pepper to taste

Instructions

  • Melt the butter in a large skillet or soup pot and add the onions. Turn the heat down and cook the onions low and slow until they turn a caramel color. Stir often.
  • Add the sliced mushrooms to the onions and cook until the mushrooms are softened.
  • Add the garlic and cook an additional minute.
  • Deglaze the pan with the white wine and simmer for a minute until the wine is mostly evaporated.
  • Add the chicken and beef broth and sprigs of thyme. Simmer for about 10 minutes, covered.
  • Pan-fry the bacon or pancetta until crisp while the soup is simmering.
  • Transfer the soup mixture to a blender – reserving about 1 cup of chunky onions and mushrooms – and puree the soup until it is thick and creamy.
  • Pour the pureed soup back into the soup pot along with the reserved soup. Bring it back to a simmer, then turn off the heat.
  • Add the cream to the soup, season with salt and pepper, and garnish with the crumbled bacon or pancetta before serving.

Notes

Chef Jenn’s Tips

  • The hardest part about making this soup is waiting for the onions to caramelize. You can use about 1 cup of leftover caramelized onions, if you have them, or do this step ahead of time. Caramelized onions will keep for a few days in the fridge.
  • Cremini mushrooms are my pick for this recipe because of their deep mushroom flavor. If you use portobello mushrooms, be sure to remove the dark gills with a spoon before cooking, or they’ll discolor your soup.
  • Half chicken broth and half beef broth is an old chef trick for coaxing great flavor out of soups without it tasting all of beef or chicken. Try it!
  • Be careful when using the blender. Hot liquids like to explode when being blended. Remove the hole in the lid and cover the top of the blender with a clean kitchen towel. Start on low and work the speed up to high until the soup is pureed.

Nutrition

Serving: 1.5cups | Calories: 222kcal | Carbohydrates: 13g | Protein: 8g | Fat: 16g | Saturated Fat: 10g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 4g | Trans Fat: 0.2g | Cholesterol: 44mg | Sodium: 364mg | Potassium: 887mg | Fiber: 2g | Sugar: 6g | Vitamin A: 579IU | Vitamin C: 7mg | Calcium: 61mg | Iron: 1mg

A Note on Nutritional Information

Nutritional information for this recipe is provided as a courtesy and is calculated based on available online ingredient information. It is only an approximate value. The accuracy of the nutritional information for any recipe on this site cannot be guaranteed.

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By Chef Jenn