A simple, bold marinade provides a ton of flavor to these hearty portobello mushroom burgers. With cooking instructions for both outdoor grill and indoor grill pans, this quick recipe is satisfying for vegetarians and meat eaters alike!
With a package of portobellos in the house, if I'm not making a portobello mushroom pizza, then odds are I'm making these portobello mushroom burgers.
Portobello mushrooms have a meatier texture than other mushrooms, making them a great stand-in for dishes traditionally made with meat. And while I would never describe their flavor on their own as "meaty" (...it's a mushroom), they absorb the flavor of a marinade wonderfully and become nice vessels for a variety of other ingredients, whether that's stuffing with cheese and breadcrumbs or piling high with your favorite burger toppings.
There are lots of ways to make portobello mushroom burgers your own, but this simple variation is my usual go-to.
Reasons to Love This Recipe
- A marinade of pantry staples provides a bold flavor that shines once the mushrooms are grilled. A dash of liquid smoke provides a no-meat, "meaty" flavor.
- This recipe for marinated portobello burgers is one that doesn't require a lot of lead time. They just need around 30 minutes to marinate.
- As written this recipe is vegetarian, and is easy to make alongside traditional burgers and toppings for a meatless option at a BBQ.
- Portobello mushrooms: As these will shrink in size as they cook, look to buy the largest portobello caps you can find at the store.
- Olive oil: Oil in a marinade tempers the sharpness from the vinegar and other ingredients.
- Soy sauce: This provides all the saltiness you need, as well as a umami note that rounds out the flavor. I recommend a reduced-sodium variety.
- Liquid smoke: While optional, just a dash of liquid smoke adds a smoky, almost "meaty" flavor -- all without the meat. A small bottle is relatively inexpensive and will last you a long time. Many of the prominent, commercially-available brands are vegan.
- Dried herbs: You can get creative here! I like a mix of equal parts dried thyme, oregano, and rosemary, but a pre-made herb/spice blend can easily work instead. If going that route, be careful that the blend you're using doesn't include salt, as you don't want the marinade to be overly salty.
- First clean your portobello caps, which includes wiping away visible dirt and removing the stem. You can see the steps in action in this post on how to clean mushrooms. Stir together all marinade ingredients in a large sealable bag and place in the portobello caps. Squish the bag to coat the mushrooms and let sit for 30 minutes.
- Heat your grill or a grill pan towards the end of the marinade time. Instructions for both will be detailed in the recipe card, while these pictures depict cooking in a grill pan. Heat grill pan over medium heat for several minutes, or until it's very hot. Optional: Toast the cut-side of the buns before cooking the portobello mushroom burgers. This way the buns stay dry and don't get soggy.
- Add the portobellos to the hot pan in a single layer with the side where the stem was facing up. Let them cook for 3-4 minutes or until grill marks appear on the underside. Rotate them 90 degrees and cook for another 3-4 minutes, or until the marks are now cross-hatched. Flip the caps over and cook for another 4-5 minutes, or until the mushrooms are tender. Then assemble into burgers.
Recipe Tips and Tricks
- Several kitchen tools really streamline the cooking process here. I bought this Lodge cast iron grill pan years ago and love using it for smaller-batch grilling recipes or for when it's bad weather outside. Cast iron handle covers are a MUST so you don't absent-mindedly grab the handle when it's still hot, and these inexpensive grill pan scrapers really help with clean up.
- Another variation I love to make of these portobello burgers is to use Worcestershire sauce in place of the soy sauce for even more "meaty" umami flavor. However note that Worcestershire sauce is not vegetarian as it contains anchovies.
- Don't let the mushrooms marinate for much longer than 30 minutes, as mushrooms are very porous and if left too long they can sog up.
- Carefully brush the grill grates or grill pan with a high-heat cooking oil before grilling the portobello mushrooms so they don't stick. If using an indoor grill pan, try not to use too much oil as pooling oil can cause smoke to form.
- As written this recipe is vegan, though if you'd like to add cheese to the top of your burger, do so during the last minute of cook time so it can melt.
The gills are edible so I leave them on while making portobello mushroom burgers. I don't find they get in the way or have an unappealing taste as they would be if you were stuffing portobellos instead.
Mushrooms have a high moisture content which gets released when they cook. Cooking the top of the cap first, with the cavity upright, allows the moisture to collect in that space. It will then get discarded when you flip the cap over so your portobello mushroom burgers aren't too wet.
As a standard baseline I like to use cheese (a vegan variety if you like), red onion, tomato slices, and leafy greens. Keep in mind that portobello mushrooms don't have much fiber and protein, so opting for more nutritious accompaniments is a good idea: whole-grain buns, avocado slices, baby kale leaves, bean or quinoa salads as a side dish, etc.
Store the leftover portobello caps separately from buns and toppings as they have a high moisture content. Reheat the portobellos in a pan set over medium heat until sufficiently warm throughout. In a pinch you can also use the microwave, though try not to overheat them in there as this can compromise the texture.
If you’ve enjoyed this recipe, I’d love for you to leave a star rating in the recipe card and/or a comment review below!
Grilled Portobello Mushroom Burgers
- 4 large portobello mushroom caps
- 4 Tablespoons balsamic vinegar
- 2 Tablespoons olive oil
- 1 ½ Tablespoons reduced-sodium soy sauce
- Dash of liquid smoke
- 4 cloves garlic minced/pressed
- ¼ teaspoon dried thyme leaves
- ¼ teaspoon dried oregano
- ¼ teaspoon rosemary sprigs chopped
- ⅛ teaspoon ground black pepper
- Oil for brushing the grill/grill pan
- 4 hamburger buns
- Your favorite burger toppings
- Wipe the portobello mushroom caps using a damp paper towel to remove dirt, then remove the stems.
- Add balsamic vinegar, olive oil, soy sauce, liquid smoke, garlic, pepper, and herbs to a large sealable bag. Stir to combine the marinade ingredients, then place the portobello caps in the bag in a single layer. Press out excess air from the bag before sealing.
- With your hands squish the mushrooms around so the marinade coats all sides completely. Let the portobellos marinate at room temperature for 30 minutes, flipping the bag over a few times throughout. Toward the end of the marinating, prepare your grilling method.
For an outdoor grill:
- Heat grill to within the medium heat range, around 350°F. Carefully dip a paper towel into a bit of oil, then use long tongs to rub it along the grill grates.
- Add the portobello mushroom caps over direct heat with the stem-side up. Cook for 8-9 minutes total or until grill marks form, rotating the caps 90 degrees halfway through if you'd like cross-hatched grill marks. Flip the caps over and brush marinade over top. Cook for another 7-8 minutes, or until the mushrooms are tender. Toward the end of the cook time, add the buns to the grill, cut-side down, and toast for a minute or so or until to your liking. Assemble burgers.
For an indoor grill pan:
- Heat pan on the stove over medium heat for several minutes, or until it's very hot. Carefully brush the grooves of the hot pan with oil, trying not to use too much as pooling oil can cause smoking. If you'd like to toast the buns, add them cut-side down until toasted to your liking, then set aside.
- Place the mushrooms in the pan in a single layer with the stem-side up. You may need to do this in batches if the pan is not large enough to fit all of them comfortably.
- Cook for 3-4 minutes or until grill marks develop, then rotate the caps 90 degrees and cook for another 3-4 minutes or until cross-hatched grill marks form (6-8 minutes total).
- Flip the caps over and cook for an additional 6 minutes or so on the other side, or until the portobellos are tender. Assemble into burgers.
- Get creative with seasonings and add your favorite dried herbs and spices to the marinade. If using a pre-made blend, make sure it doesn't include salt as you don't want the marinade to be too salty.
- Mushrooms are very porous so don't allow them to marinate for too much longer than 30 minutes, as you run the risk that they become soggy.
- If using a cast iron grill pan, use caution not to touch the handle as it gets very hot! Cast iron handle mitts are very useful.
- Store leftover cooked portobello caps separately from buns/toppings. Reheat them in a hot pan until heated throughout, or give them a spin in the microwave (taking care not to cook them too long in there as this can lead to a more rubbery texture).
Nutritional information is provided as an estimate. As it can vary due to many factors (brands used, quantities, etc.), we cannot guarantee its accuracy.Food Safety and Nutrition Disclaimer