Rich and Creamy Vegan Mushroom Soup (No Cashews!)

This vegan mushroom soup is creamy and earthy, made in one pot with simple ingredients. No cashews, no blender, just a velvety broth that comes together in about 35 minutes.

It’s the kind of meal that feels like a slow Sunday but works on a busy Tuesday. I make it when I want something warm that still tastes fresh and deeply savory.

What Makes This Soup So Good

The creaminess comes from a quick flour roux and rich oat milk, so you skip the soaking and straining of cashews entirely. The soup stays smooth without a blender.

The mushrooms carry the flavor. I use a mix of cremini and shiitake for layers of earthiness, then add thyme and a finish of lemon juice to keep it bright. Every spoonful tastes like real mushrooms, not just a bowl of cream.

Ingredients

• 2 tbsp olive oil: or another neutral oil
• 1 medium onion, diced: yellow or white
• 3 cloves garlic, minced
• 1 lb cremini mushrooms, sliced: same as baby bellas
• ½ lb shiitake mushrooms, sliced: stems discarded
• 2 tbsp all-purpose flour: use 1½ tbsp cornstarch mixed with 2 tbsp cold water for gluten‑free
• 4 cups vegetable broth: low‑sodium so you control the salt
• 1 cup unsweetened oat milk: the full‑fat barista version gives the creamiest result
• 1 tsp dried thyme: or 1 tbsp fresh thyme leaves, plus extra for garnish
• ½ tsp salt: plus more to taste
• ¼ tsp black pepper
• 1 tsp lemon juice: brightens the broth

Variations / Substitutions

• Mushrooms: Swap in oyster mushrooms or plain white buttons if that’s what you have. The flavor will be a little milder.
• Herbs: Fresh dill or tarragon stirred in at the end gives a different herbal note.
• Gluten‑free: Replace the flour with 1½ tbsp cornstarch dissolved in 2 tbsp cold water; stir in after the broth comes to a simmer.
• Richer broth: Use an equal amount of canned full‑fat coconut milk instead of oat milk for a thicker, rounder finish.

If you like simple plant‑based soups, you might also enjoy our lentil soup.

How to Make Vegan Mushroom Soup

Step 1: Sauté the Aromatics

Heat the 2 tbsp olive oil in a large pot over medium‑high heat. Add the diced onion and cook for about 5 minutes, stirring often, until it turns translucent and soft. Toss in the minced garlic and cook 1 minute more, just until the raw garlic smell fades.

The onion will release a little sweetness as it softens, and the garlic will smell sharp and nutty right before you move on.

Step 2: Cook the Mushrooms

Add the sliced cremini and shiitake mushrooms to the pot, along with the ½ tsp salt. Give everything a good stir. Cook for 8 to 10 minutes, letting the mushrooms release their liquid first, then brown in the dry spots. You want deep golden edges all over.

The mushrooms will shrink by about half and turn a rich brown. The kitchen will smell earthy and toasted, which is exactly right.

Step 3: Build the Creamy Broth

Sprinkle the 2 tbsp flour evenly over the mushrooms and stir constantly for 1 minute. This cooks the raw flour taste out. Now slowly pour in the 4 cups vegetable broth, stirring as you go to break up any lumps. Add the 1 tsp dried thyme and bring everything to a low simmer.

The broth will look pale and a little thin at first. That’s fine; it thickens as it simmers.

Step 4: Simmer and Finish

Reduce the heat so the soup bubbles gently. Stir in the 1 cup oat milk and let the soup simmer, uncovered, for 5 to 7 minutes, until it coats the back of a spoon. Take it off the heat, then stir in the 1 tsp lemon juice and the black pepper. Taste and adjust salt if needed.

The finished soup should feel velvety and glossy, with visible flecks of thyme and mushroom bits suspended in the creamy base.

Step 5: Ladle and Serve

Ladle the soup into bowls while it’s hot. Scatter a few fresh thyme leaves on top and add a black pepper crack if you like. Serve right away.

Tips for the Best Mushroom Soup

• Use dry mushrooms for deeper flavor.: If you have a handful of dried porcini, soak them in hot broth for 10 minutes, then chop and add them with the fresh mushrooms. The soaking liquid can replace part of the broth.
• Don’t wash the mushrooms in water.: Wipe them clean with a damp paper towel so they don’t soak up extra moisture and steam instead of browning.
• Give them space.: If the pot is too crowded, mushrooms steam instead of sear. Cook in batches if your pot isn’t wide enough for a single layer.
• A splash of sherry works wonders.: Add 2 tbsp dry sherry after the mushrooms brown, letting it cook off before the flour step, to add a savory depth.
• Reheat gently.: Leftover soup thickens in the fridge. Warm it over low heat with a splash of broth to loosen it without scorching the bottom.

Storing Leftovers

• Refrigerate: Cool the soup completely and store in a sealed container for up to 4 days.
• Reheating: Warm it in a pot over medium‑low heat, stirring often. Add a little broth or water if the soup has become too thick.
• Freeze: You can freeze it, but the oat milk may separate slightly. Thaw overnight in the fridge, then whisk vigorously while reheating to bring the texture back.

What to Serve with Creamy Mushroom Soup

A thick slice of crusty sourdough toast is the obvious match, and for good reason: the tangy, chewy bread soaks up the creamy broth without turning to mush. If you want something lighter, a simple arugula salad with a sharp lemon vinaigrette cuts through the richness. For a bigger meal, roasted root vegetables like carrots or parsnips sit nicely alongside a bowl of this soup.

Frequently Asked Questions

Can I use dried mushrooms instead of fresh?

Yes. Soak about 1 ounce of dried porcini or shiitake in hot broth for 10 minutes, then chop them and use the strained soaking liquid as part of the broth.

What’s the best plant milk for creamy soup?

Unsweetened oat milk gives the smoothest, creamiest result without a strong coconut taste. Soy milk works too, but it can curdle if boiled hard, so keep the heat low.

How do I make this soup nut‑free?

It already is. There are no cashews, almonds, or nut milks in the ingredient list.

My soup turned out too thin. What went wrong?

The roux likely didn’t cook long enough, or the soup didn’t simmer for the full time. Simmer it a few minutes longer, or stir in a little cornstarch slurry to thicken it quickly.

Vegan Mushroom Soup Recipe

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Prep Time 10 minutes mins

Cook Time 25 minutes mins

Total Time 35 minutes mins

Servings: 4 servings

Calories: 152

Ingredients Method Notes

Ingredients

  

• 2 tbsp olive oil
• 1 medium onion, diced
• 3 cloves garlic, minced
• 1 lb cremini mushrooms, sliced
• ½ lb shiitake mushrooms, sliced
• 2 tbsp all-purpose flour
• 4 cups vegetable broth
• 1 cup unsweetened oat milk
• 1 tsp dried thyme
• ½ tsp salt
• ¼ tsp black pepper
• 1 tsp lemon juice

Method

 

1. Heat olive oil in a large pot over medium‑high heat. Sauté onion for 5 minutes until soft, then add garlic and cook 1 minute.
2. Add mushrooms and salt. Cook 8 to 10 minutes, stirring occasionally, until mushrooms release liquid, shrink, and turn golden brown.
3. Sprinkle flour over the mushrooms and stir for 1 minute. Slowly pour in vegetable broth, stirring constantly, then add dried thyme. Bring to a low simmer.
4. Stir in oat milk, reduce heat, and simmer gently for 5 to 7 minutes until the soup thickens and coats a spoon. Remove from heat and stir in lemon juice and black pepper. Taste and adjust salt.
5. Ladle into bowls and top with fresh thyme leaves. Serve hot.

Notes

The soup thickens as it cools because the flour continues to absorb liquid. If making ahead, reheat with a splash of broth to loosen it. For the glossiest finish, use a full‑fat oat milk labeled “barista” or “extra creamy.”