Portobello Mushroom Buns

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Portobello Mushroom Buns are the perfect way to hold your sandwich or burger fillings on a Whole30, Paleo, or Low Carb diet.


Portobello Mushroom Buns are my favorite low carb/Whole30 option when it comes to sandwiches and burgers. Their meaty texture ensures they won't fall to pieces and since I find their mild, earthy flavors taste good with almost anything.

These buns have been a lifesaver over the past month. Embarking on a Whole30 for the first time quickly left me craving my favorite burgers and sandwiches. Let's be real, I was craving bread, but I figured if I could at least have a sandwich then maybe I could quell the beast.

Looking at Whole30 "bread" options, people go in a few directions. Sweet potato, collard greens, lettuce, and mushrooms seem to be the most popular. People also use cucumbers, tomatoes, eggplant, roasted red peppers, and zucchini. That's a lot of options but mushrooms immediately jumped out at me since I love them. The idea of a grilled or roasted mushroom cradling my sandwich filling sounded dreamy.

And it was! I have since used them for burgers, BLT's, egg sandwiches, and basically, any kind of sandwich you can think of that is Whole30 approved. Yum.

How to Make a Portobello Mushroom Bun

These mushroom buns can be made in the oven or on the grill. Here's what to do.

  • Clean the mushrooms: Portobello mushrooms can have some dirt and debris so it is important to clean them. The best way is to simply wipe away any dirt using a moist paper towel. Then use a spoon to gently remove the gills and stem. Many store-bought mushrooms will already have the gills and stem removed. This step is optional., but many people prefer the texture of the mushroom without the gills.
  • Brush with oil: Brush the mushroom on both sides with olive oil or another cooking oil. This adds flavor and ensures it won't stick to the baking sheet or grill. 
  • Season: To make sure the mushroom is nice and flavorful, give it a good sprinkle of salt and pepper. You can add any additional seasoning you like as well including dried herbs, red pepper flakes, garlic powder, or spice blends.
  • Roast or grill: Cook it in a preheated oven or on a hot grill. It will take 10-12 minutes in the oven or 4-5 minutes per side on the grill. Make sure not to overcook the mushroom or it can get soggy. If the mushroom is wet at all, simply blot it with a paper towel. 

What to Serve in a Mushroom Bun

Almost anything tastes good in a mushroom bun. In fact, it is one of my favorite ways to serve a burger whether or not I am eating low carb. Here are some of my favorite fillings:

These mushroom burger buns are also delicious with simple ground beef burger patties. Add cheese (not for Whole30), lettuce, tomato, onions, pickles, avocado, and your favorite sauce. We also love them for breakfast sandwiches with sausage and fried eggs.

Don't forget to try these open-faced as well! They make a delicious open-faced sandwich or can be used to make portobello pizzas

Frequently Asked Questions

Here are some of the most common questions about making these mushroom burger buns.

These can be made up to 2 days ahead of time but they will soften as they sit in the fridge. Make sure to dry them if they become wet and then reheat in the oven or microwave.

The gills of a portobello mushroom are edible but they tend to have a fibrous texture so it is best to remove them. They can be gently scooped out with a spoon or you can simply use your hand to peel them out of the mushroom cap.

If you prefer the taste of raw mushrooms, use the cap of the portobello as a burger bun without cooking it. Just make sure to clean away any debris and remove the stem and gills.

The Recipe
Portobello mushroom buns with grill marks on a grill.

Portobello Mushroom Buns

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  • 2 portobello mushrooms
  • 1/2 tbsp. olive oil
  • Salt and pepper

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Preheat the oven to 450 degrees. Remove the gills from the mushroom.


Brush the mushrooms with olive oil and sprinkle with salt and pepper. Add any other seasoning or fresh herbs as well.


Roast for 10-12 minutes until mushroom are tender.


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Nutritional Facts
Serving Size: 1
Amount Per Serving
Calories 68
Calories from Fat 62
% Daily Value *
Total Fat 7g
Saturated Fat 1g
Monounsaturated Fat 0g
Polyunsaturated Fat 0g
Cholesterol 0mg
Sodium 2mg
Total Carbohydrate 1g
Dietary Fiber 0g
Sugars 1g
Protein 1g

* Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

The Nutritional Values provided are estimates only and may vary based on the preparation method.

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About the author Meet Kristen McCaffrey
Hi, I’m the cookbook author, recipe developer, and food enthusiast behind Slender Kitchen. I am obsessed with making healthy food that is easy to prepare and absolutely delicious. Meal planning is my secret weapon and I hope I can make meal time easier for you with our tried and tested recipes and foolproof meal plans. Learn More
On Portobello Mushroom Buns
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December 13, 2021 - 18:02
Add a Rating:
First time trying a faux bun and these were great! I added a little Italian seasoning. We’re nice and firm and stayed together!
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Bonnie Dorman
November 14, 2020 - 11:05
Can you make these in advance?
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November 18, 2020 - 09:02
Yes! Let them cool after cooking and them just store in the fridge. Reheat in a skillet or the microwave. They will be slightly less firm but still delicious.
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