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Creamy Mushroom Onion Boil

4.8/5
5 reviews
Creamy Mushroom Onion Boil
Creamy Mushroom Onion Boil
260min Total Time
6 people Servings
Easy Difficulty
Budget Cost
245 kcal Calories

Ingredients

6
  • 2 lbs mixed mushrooms (button, cremini, shiitake), sliced
  • 3 large yellow onions, thinly sliced
  • 4 cups vegetable broth
  • 1 cup heavy cream
  • 4 cloves garlic, minced
  • 2 tablespoons butter
  • 2 tablespoons fresh thyme leaves
  • 1 tablespoon Worcestershire sauce
  • 2 teaspoons cornstarch (optional, for thickening)
  • 1 teaspoon black pepper
  • 1 teaspoon sea salt

Instructions

1

Place sliced onions in the bottom of the slow-cooker

2

Layer sliced mushrooms on top of the onions

3

Add minced garlic, thyme, salt, and pepper

4

Pour in vegetable broth and Worcestershire sauce

5

Cover and cook on LOW for 6-8 hours or HIGH for 3-4 hours

6

In the last 30 minutes, stir in the heavy cream

7

If desired, whisk cornstarch with 2 tablespoons cold water and stir into the mixture to thicken

8

Add butter and let it melt into the mixture

9

Taste and adjust seasonings as needed

10

Let rest for 10 minutes before serving to allow sauce to thicken

Troubleshooting

If sauce is too thin, add cornstarch slurry in final cooking stage
If mushrooms release too much liquid, leave lid slightly ajar for last hour
If cream curdles, lower heat and whisk in fresh cream at the end
If flavors are bland, add more Worcestershire sauce and seasonings
If onions aren't tender enough, increase cooking time by 1 hour

Recipe Variations

French-style: Add white wine and herbs de Provence
Asian-inspired: Include soy sauce and sesame oil
Italian version: Add Parmesan and Italian herbs
Swedish style: Include dill and a touch of mustard
Hungarian variation: Add paprika and sour cream

Serving Suggestions

Serve over buttered egg noodles or rice
Pair with crusty sourdough bread for dipping
Top with fresh parsley and extra black pepper
Serve alongside roasted green vegetables
Garnish with additional fresh thyme leaves

Nutrition Facts

245
Calories
8g
Protein
15g
Carbs
18g
Fat

Common Mistakes to Avoid

Adding cream too early in the cooking process
Using too much liquid which dilutes flavors
Not slicing onions thinly enough for proper cooking
Opening the slow-cooker lid too frequently
Forgetting to season adequately throughout layers

Frequently Asked Questions

Can I use dried mushrooms?

Yes, rehydrate them first in hot water and use the soaking liquid as part of your broth.

Is this recipe freezer-friendly?

Yes, but freeze before adding cream and add fresh cream when reheating.

Can I make this dairy-free?

Yes, substitute cream with coconut cream or cashew cream.

How do I prevent the cream from curdling?

Add it during the last 30 minutes of cooking and keep temperature on LOW.

Can I use frozen mushrooms?

Fresh mushrooms are preferred, but frozen can work - expect more liquid release.

How do I thicken the sauce?

Use cornstarch slurry in the last 30 minutes of cooking.

What type of mushrooms work best?

A mixture of varieties provides the best flavor and texture.

Can I cook this on HIGH instead of LOW?

Yes, reduce cooking time to 3-4 hours on HIGH.

Why are my mushrooms rubbery?

They might be overcooked - try reducing cooking time slightly.

Can I add other vegetables?

Yes, hardy vegetables like carrots work well added at the beginning.

Reviews

Viktor P.
Mar 10, 2026
Perfect comfort food! The mushrooms were so tender and flavorful.
Zara M.
Mar 6, 2026
Great recipe, though I needed to add more seasoning for my taste.
Xavier C.
Mar 30, 2026
The slow cooking really brings out the mushroom flavor beautifully.
Yuki T.
Mar 6, 2026
Easy to make and very satisfying. Will make again!
Winston R.
Mar 4, 2026
Best mushroom recipe I've tried in my slow-cooker.
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