You don’t have to give up beef to love these portobello burgers. A 3-ingredient marinade creates incredible flavor, and they’re simple to cook in the oven or on the grill.
You don’t have to give up beef to love these portobello burgers. They’re tender, meaty, incredibly satisfying.
A simple, three-ingredient marinade heightens the mushrooms’ natural umami, and conveniently, an extended soak time isn’t necessary. With the following simple recipe and a few helpful tips, you may find portobellos to be a welcome way to add variety to the typical burger night.
Do keep in mind that, without a bun, the mushrooms also make a great side dish. And conveniently, they can be prepared in tandem with beef or turkey burgers when serving family and friends who follow vegan and vegetarian diets.
Shopping Tip: For the best burgers, look for the biggest portobellos – aim for a diameter that’s a little wider than the bun. If you can only find smaller portobellos, you may wish to plan on two per bun.
To remove the gills or not?
The gills are edible, so this is really a matter of personal preference. I’ve prepared the mushrooms both ways but usually scrape them out because many people seem to prefer them that way.
Note that, when mixed with other foods, the gills can turn the food a murky brown color.
The Marinade
Based off my Essential Marinade (also known as “a third-a third-a third marinade” because it consists of equal parts of three basic ingredients), this mixture couldn’t be easier or more flavorful. (If you haven’t t made this grilled chicken, you must!)
The lemon juice, soy sauce, and olive oil combination is poured over the portobellos – I use my hands to rub it all over – and it really brings out the savory, meaty qualities of these mushrooms.
A soak time of 15 minutes is all you need. A little longer is fine, but I tend to not go more than an hour or so. The excess marinade is drained before cooking, although I reserve it and, when grilling, often baste once at the end. I don’t baste when cooking in the oven, as the released liquid creates a moister environment.
No worries if you skip the baste when grilling though. Short of burning them, it’s hard to overcook or dry out the mushrooms; their high moisture content virtually ensures a tender, juicy outcome. A final baste will simply add a glowing sheen and an extra kiss of flavor.
The Toppings
Lettuce, thinly sliced red onions (or Pickled Onions), avocado or guacamole, and sriracha mayo or Smoked Paprika Aioli are our go-tos, as is cheese. Gruyere, Fontina, Swiss, Gouda, Colby, Monterey Jack, sharp cheddar, and Provolone are all great options.
One of my favorite cheeses on these burgers, however, is herby Boursin cheese. I let it soften to room temperature and then spread it on the hamburger buns. If I forget to soften it, I warm it briefly (10 second bursts) in the microwave. You want it to be spreadable but not melted.
Optionally, you can melt the cheese in the mushroom. In this case, you will want to put the cheese in the cavity of the mushroom towards the end of cooking time, making sure all moisture is drained away first. If you put the cheese on the domed side of the mushroom, it will slip off as it melts!
A final alternative is to melt cheese on the buns as you toast them in the oven, toaster oven, or on the grill (being especially careful not to burn them on the grill, especially with brioche rolls, as the butter in them tends to hasten the burn time). I also find that, when distributed over the bun instead of the portobello, you’re guaranteed to get cheese in every bite.
I’d love to know if you try this recipe. Leave a comment, rate it, and don’t forget to tag a photo @fountainavenuekitchen on Instagram and Facebook. Your feedback is always appreciated.
Portobello Mushroom Burgers (Roasted or Grilled)
Ingredients
- 4 portobello mushrooms caps (look for large ones, ideally at least as wide as a hamburger bun)
- 2 tablespoons (30ml) low-sodium soy sauce or gluten-free tamari
- 2 tablespoons (30ml) freshly squeezed lemon juice
- 2 tablespoons (28ml) olive or avocado oil
- 4 hamburger buns, toasted
- Optional toppings: arugula, butter lettuce, baby spinach, or greens of choice; sliced or mashed avocado; cheese (like Boursin*, blue cheese, fontina, gruyere, Swiss, provolone, or mozzarella), sriracha mayo (see notes); pesto; sliced tomato; thinly sliced red onion or pickled onions; thinly sliced cucumber; and/or other favorite burger toppings
Instructions
- Prep the portobellos: Use a paper towel to gently rub the portobello mushrooms to help remove any dirt and trim the stem if it is prominent. With a soup spoon, scrape out the gills and discard. (Technically, the gills are fine to eat if you prefer to skip this step.) Arrange the portobellos in a glass baking dish with the stem-side facing up. (Alternatively, you could use a large, zip-top bag.)
- Marinate the portobellos: In a small bowl, stir together the soy sauce, lemon juice, and olive oil. Use a spoon to pour the mixture over the mushrooms, and then use your hands to rub the sauce on the outside of the mushrooms too. (If using a zip-top bag, seal, and gently move around to coat them in the marinade.) Let the portobellos marinate for 15 minutes or so.
- To roast the portobellos: Preheat the oven to 400ºF. Drain off the excess marinade and place the mushrooms, stem-side up, on a lightly greased or sprayed baking sheet. (For easy cleanup, line with foil or parchment.) Roast the mushrooms for 15 minutes, and then flip them over (before flipping, I pour off any accumulated liquid – mushrooms emit a lot) and bake for an additional 10 minutes or until the mushrooms are tender.
- If using cheese: Drain off additional liquid as needed. If desired, top with cheese and roast another 1 minute until the cheese melts. Or you can put the cheese on the toasted bun and place back in the toaster or oven for a minute to melt.
- To grill the portobellos: Follow the same instructions but cook on a grill that has been preheated to medium. Start with rounded side down, grilling (with lid down) for 5-7 minutes, depending on thickness, until lightly browned. Flip and cook the other side for about 3-5 minutes more. (It’s tough to overcook the mushrooms; they won’t be dry as they are naturally very high in moisture. You just don’t want to burn them with too much direct heat. More than focusing on time, I look for nice grill marks and deep golden color.)
- If using cheese, you can flip the mushrooms back over and place the cheese on top (in the concave part, not on the rounded side where it will likely slide off). Close the lid for a minute or so to allow the cheese to melt. Or add the cheese to the toasted bun towards the end of toasting to get it a little melty.
- Serving: With either method, serve warm on a toasted bun with your favorite toppings.
- Storage: Leftover mushrooms can be stored in an airtight container in the fridge for 3-4 days.
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