Meatless Monday Challenge

Grilled Portobello Mushroom Steak

on May 30, 2023
last updated May 4, 2024
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This Grilled Portobello Mushroom Steak recipe is hearty, savory, and smokey, with a quick 30-minute marinade and simple grilling technique!
Grilled Portobello Mushroom Steak with mashed potatoes and asparagus

Looking for a hearty, smokey meatless main? This Grilled Portobello Mushroom Steak is meaty in texture, smokey and savory in flavor, and brings tons of abundance to any meal.

Plus, it only requires 6 ingredients, 30 minutes to marinate, and cooks quickly on either an outdoor grill or inside on a grill pan. If you love mushrooms, there’s no doubt you will love this portobello mushroom recipe!

In this recipe you will learn how to prep your portobellos, whip up a quick marinade for them, and grill them to perfection.

Grilled Portobello Mushroom Steak close up

As an environmental scientist, I’m always looking for delicious meat alternatives to help me lower my ecological footprint, and the mushrooms in this recipe are an incredible replacement for steak!

Just like in this Vegetarian Philly Cheesesteak recipe, the “meaty” texture of the portobello mushrooms lends itself to the flavorful marinade and has a similar mouthfeel to meat.

Green tip: Industrial meat production has a huge impact on the environment, especially because of the amount of land it takes to sustain and its high amount of greenhouse gas emissions. Reducing your meat consumption is one great way to reduce your ecological footprint.

Portobello Mushroom Steak Ingredients

Here’s everything you need:

  • Portobello mushrooms. The star of this dish!
  • Garlic. For tons of flavor.
  • Olive oil. So that the mushroom doesn’t stick to the pan.
  • Balsamic vinegar. For subtle sweetness and acidic flavors.
  • Steak seasoning. You can use your favorite! I used Montreal Steak Seasoning. Or, if you really want that from-scratch taste, make your own Steak Seasoning.
  • Liquid smoke. While this is optional as I know it is not always a typical pantry item, and you will get some smokiness from grilling, I do recommend it to get the smokiest and meatiest flavor.
ingredients for portobello mushroom steaks - balsamic vinegar, olive oil, portobello mushrooms, garlic, steak seasoning, liquid smoke

Portobello Mushroom Steak Tips and Tricks

How to Clean and Prep Portobello Mushrooms

The best way to clean your mushrooms is to do so dry. You can either use a kitchen towel or clean hands to wipe any visible dirt off of them. Rinsing mushrooms may actually cause them to get a little slimy and/or soggy, and that sliminess can remain even after grilling!

Then, carefully remove the stems of the mushrooms. The stems of portobellos are a little tough and woody, but the primary reason we are removing them is so the mushrooms can sit flat on the grill.

The stems are completely edible and can be saved in the freezer to make your own veggie broth, added later to another dish, like this Mushroom Fried Rice, or composted!

In a lot of my recipes that contain portobello mushrooms, I like to keep the stems on to reduce waste. Although the stems are a little bit tougher in texture, they do soften as they cook if they are sliced.

However, in this mushroom steak recipe, it’s important to remove the stems so that the mushroom caps can easily lay flat on your grill or grill pan.

Wiping dirt off of portobello mushrooms instead of rinsing to clean
Wipe your portobello mushrooms clean.
Two portobello mushrooms with stem removed
Remove the stems from your portobello mushrooms.

How to Mince Garlic

In order to effectively mince your garlic, you’ll have to peel it first! To peel the outer layer off easily, I like to crush the garlic clove first.

Lay the garlic cloves flat on your cutting board and use the flat end of your knife to press down on the garlic. You’ll hear a distinct crunch when it’s crushed.

This will crack open the outer layer and make it much easier for you to peel that layer back. Once you’ve completely peeled your garlic, it’s time to mince it!

Chop the garlic with a sharp knife until you’re left with tiny pieces.

Peeling garlic to mince it
Peel the garlic cloves first.
Mincing garlic to add to marinade for portobello mushrooms
Then, use a sharp knife to mince it.

How to Quickly Marinate Mushrooms

This recipe is deigned to quickly add deep flavor to the mushrooms, without having to marinate them for hours on end. I like to marinate my mushrooms in a sealed bag.

Green tip: Reduce your plastic waste by investing in easy-to-clean reusable storage bags!

Using a bag allows you to evenly distribute the marinade around the mushrooms, sealing the mushrooms and the marinade inside.

Plus it’s easy and requires little clean-up. Just drop your prepped mushrooms into the bag followed by all of the marinade ingredients.

Seal the bag and shake it vigorously. Every so often, give the bag a shake, to ensure the whole mushroom is coated. Leave the mushrooms to marinate for 30 minutes to allow the flavors to seep in.

Adding marinade ingredients to large bag with portobello mushrooms
Add the mushrooms and all the marinade ingredients to a storage bag.
Large reusbale bag with portobellow mushrooms and marinade
Seal the bag and shake to coat. Then, allow the mushrooms to marinate in the bag at room temperature, moving it around occasionally to evenly distribute the flavors.

How to Use a Grill Pan for Mushrooms

A grill pan is a great way to get a smoky flavor and those coveted grill marks, without having to fire up your grill.

Start by getting the grill pan hot. Place the pan over medium-high heat and allow it to sit for 3-5 minutes to get hot before adding your mushrooms.

Once your grill pan is hot, carefully place your marinated portobello mushroom steaks directly on the hot grill pan, with the smooth part of the mushroom cap facing up first. Cook over medium-high heat for 5 minutes. There should be some steam!

After 5 minutes, flip the mushroom and cook with the smooth side of the cap down for another 5 minutes. Every couple minutes, push down on the mushroom with your spatula or tongs, to help sear it and get those grill marks.

After 5 minutes, check if the mushroom is ready to flip one last time. You’ll know it’s ready to flip again because it will easily peel away from the grill pan. If it’s stuck, give it another 2-3 minutes. When it’s ready to flip, it will release from the pan.

Once flipped for the second time, cook for a final 2 or 3 minutes, just to allow any excess liquid to release, produce some smoke, and add some additional smokey flavor to the mushrooms.

Placing portobello mushrooms face down on grill pan
Get the pan hot first, so when you place the portobello mushrooms on them, they immediately start to sizzle and steam.
Using tongs to flip portobello mushrooms in grill pan
After 5 minutes, flip the mushrooms, so that the smooth side of the cap is facing down.
Grilling second side of mushrooms in grill pan
Cook for another 5 minutes on the second side, then flip one last time to release any excess liquid into the pan.

How to Grill Portobello Mushrooms on an Outdoor Grill

Grilling portobello mushrooms on an outdoor grill is identical in method to using a grill pan. Make sure to preheat the grill to high. It should be nice and hot by the time you place your mushrooms on the grate.

Place the mushrooms with the smooth side of the cap up first, grilling for about 5 minutes. Then, flip the mushroom cap, so that the smooth side is directly on the grill. Cook for about 5 more minutes, before flipping one last time to remove excess liquid.

Green tip: For the lowest carbon emissions, consider a liquid propane grill (as opposed to charcoal, and woodburning), which on average emit 1/3 the amount of carbon.

How to Serve Your Portobello Mushroom Steak

You can serve these Portobello Mushroom Steaks just as you would a steak dinner! Here are some of my favorite sides to serve up with these grilled portobellos:

And if you’re looking for a delicious sauce to serve overtop, consider one of these:

Portobello Mushroom Steak with forkful taken out

How to Properly Store and Reheat Portobello Mushroom Steak

Leftover Portobello Mushroom Steak last in the refrigerator for 3-4 days in an airtight container. They can also be frozen for up to 3 months.

My favorite way to reheat leftover grilled portobello mushrooms is in the oven. Preheat the oven to 350°F and heat them on the top rack for 10-15 minutes until heated all the way through.

Green tip: Did you know that of the billions of pounds of food wasted annually, it is estimated that 50% of it happens in our homes? Reduce your contribution to food waste by properly storing and enjoying your leftovers!

Why You Should Make this Grilled Portobello Mushroom Steak

  • The texture! Super meaty, hearty, and filling.
  • They’re simple to make. Just 6 ingredients and about 15 minutes of active cooking time.
  • The quick marinade! No need to marinade for hours on end, this recipe gives you tons of flavor with just 30 minutes of marinading.

If you’re loving this Grilled Portobello Mushroom steak recipe and want more hearty meatless mains, check out these Tofu Fajitas with Onions and Peppers and Vegan Tempeh Bolognese.

Grilled Portobello Mushroom Steak with mashed potatoes and asparagus

Grilled Portobello Mushroom Steak

5 from 6 votes
Marley Goldin
This Grilled Portobello Mushroom Steak recipe is hearty, savory, and smokey, with a quick 30-minute marinade and simple grilling technique!
Prep Time 3 minutes
Marinating Time 30 minutes
Cook Time 12 minutes
Total Time 45 minutes
Servings 2 mushroom steaks


  • 2 large portobello mushrooms
  • 2 cloves garlic
  • ¼ cup extra-virgin olive oil
  • 3 tablespoons balsamic vinegar
  • 1 teaspoon steak seasoning
  • 1 teaspoon liquid smoke (optional)


  • Clean your mushrooms and remove the stems, and peel and mince your garlic cloves.
    Two cleaned Portobello mushroom caps on a plate
  • Add the mushroom caps to a large storage bag (use a reusable storage bag for a more sustainable option!) with the minced garlic, olive oil, balsamic vinegar, steak seasoning, and liquid smoke (optional).
    Portobello Mushrooms and quick marinate in bag
  • Seal the bag and shake to coat the mushroom in all the marinade ingredients and set aside at room temperature to marinate for 30 minutes. Move it around every 10 minutes or so if you can, just to ensure the flavors are evenly distributed.
    Portobellos marinating in a reusable storage bag
  • Preheat your grill to high or get a grill pan hot over medium-high heat. Carefully place your mushroom on the grill grate or grill pan with the smooth side facing up. Grill for 5 minutes.
    Grilling portobello mushrooms on a grill pan
  • After 5 minutes, flip the mushroom so that the smooth side is directly on the grill. Grill for another 5 minutes. Then, flip one more time to release excess liquid.
    If the mushroom is stuck to the grill or the grill pan, give it another 2-3 minutes before flipping. Do not force it. The mushroom will release from the grill or pan when it's ready to flip.
    Flipping and grilling portobello mushrooms on a grill pan again
  • Serve hot! I love to enjoy my Mushroom Steaks with these Truffle Mashed Potatoes and Roasted Asparagus and Carrots.
    Grilled Portobello Mushroom Steak with mashed potatoes and asparagus

Pro Tips

  • Best practice for cleaning your portobello mushrooms is using clean hands or a kitchen towel to wipe them clean. Rinsing them with water can lead to slimy or soggy mushrooms. 
  • For more ‘shroom recipes, check out this list of Best Mushroom Recipes!
Course Dinner
Cuisine American
Diet Vegan, Vegetarian
Keyword Grilled Mushrooms, Mushrooms, Portobello Mushroom Steak, Portobello Mushrooms
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7 thoughts on “Grilled Portobello Mushroom Steak”

  1. Jennifer Wager

    5 stars
    We really enjoyed these – very moist. I didn’t have steak seasoning so used some Old Bay which worked well. Will certainly do this recipe again.

  2. Jennifer Wager

    5 stars
    We’ve just had this for lunch – really good choice for a light summery meal – we had a salad with it including home grown freshly picked lettuce leaves. The mushrooms were delicious and it was so quick and easy to prepare and cook. Certainly will do it again.

  3. 5 stars
    I’m really looking forward to trying this out – I’m glad you said that it works just as well on the outdoor grill – we’ve just ordered a new BBQ and needed some fresh inspiration for veggie BBQ recipes, so thanks for that!

5 from 6 votes (2 ratings without comment)

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