While beef burgers are my usual go-to, I have a wide range of meatless burgers that I love (especially in months when we are reducing out meat intake), and the top of the list is today’s recipe for sautéed Portobello Mushroom Burgers.
These giant mushrooms cook into a gloriously flavoursome burger filling, making them an ideal vegetarian option. However, I promise, meat eaters love them too!
Why this recipe works
The simple trick with these burgers is giving the mushrooms a quick bath in a balsamic, soy and garlic marinade. They soak up all that fantastic salty, tangy flavour which then caramelizes when you sauté them in the pan or grill.
Portobello mushrooms are big and sturdy with a lovely meaty texture, so they can hold their own against other burger fillings.
To make the perfect Portobello Mushroom Burger, you’ll need the following main ingredients:
- Portobello Mushrooms: The star of the show! Many people don’t realize that they are, in fact, enormous, grown-up cremini or crimini mushrooms! The large portobello mushroom caps are the size of a burger patty, which makes them ideal for this dish. Look for lovely, fresh mushrooms for the best results.
- Balsamic Vinegar and Soy Sauce: These two flavour powerhouses team up to make our marinade with garlic and oregano. The Balsamic provides a tangy hit which caramelizes in the pan, while the soy gives a big boost of salty umami flavour, which supercharges the mushroom flavour.
- Baking Potatoes: What are burgers without fries? I like to serve these juicy, earthy burgers with thick-cut potato wedges. Pro tip: look for potatoes labelled as suitable for baking or floury potatoes. Waxy potatoes take too long to cook and are too firm for this cooking method.
- Burger fillings: EVERYONE has their favourite burger fillings, so I don’t want to tell you what you should load your burgers up with. Swiss-style cheese (Gruyere, Emmentaler etc.) is a natural partner for mushrooms. I like to add some quick pickled red onions and fresh tomato slices or sun-dried tomatoes. They’d be great with a bit of caramelized onion too.
- Harissa Mayo: My special burger sauce couldn’t be easier to make. Simply stir a little harissa paste with your favourite mayo and perhaps a little squeeze of lemon juice, and you have a fabulous spicy burger sauce. Yum!
The complete ingredient list and instructions are in the recipe card at the bottom of this page.
These burgers are SO simple to make. In fact, most of the work is in preparing your sides and toppings. Basically, it breaks down like this:
- First, prep all your burger toppings, slice your tomatoes and wash your salad. (You’ll be a happy, organized chef if you’ve got it all ready to go before you start cooking. Take my word for it).
- Next, get your oven nice and hot, slice and toss your potato wedges with some oil and spices, then roast to golden brown perfection. (I like floury potatoes like these because they crisp up nicely on the outside while remaining soft and gorgeous on the inside. Yum.)
- Whisk together your marinade and dunk the tops of the mushrooms in, turning to cover, then lay them on a plate, and tear off the stems (you can chuck the stems in the freezer and save them for a soup or bolognese if you like), then pour over the remaining marinade. I like to leave them to soak up the marinade for about 20 minutes.
- Then all you have to do is cook those big, beautiful mushrooms for 4 minutes on each side until they are a deep caramelized brown, throw them under the grill/broiler to melt some cheese on top, then pile them onto buttery brioche buns with the fillings of your choice. Yum!
FREQUENTLY ASKED QUESTIONS
Is this recipe vegan?
To make this a vegan recipe, replace the cheese and mayonnaise with vegan alternatives. You can find an easy recipe for vegan mayo with my other favourite veggie burger recipe here.
Can I cook portobello mushrooms on a grill?
Yes! These burgers are fabulous on an outdoor grill or indoor grill pans. Just be sure that the grill itself is well seasoned to prevent the mushrooms from sticking to the grill grates. You’ll have lovely grill marks on the burgers, which makes them look even more delicious.
Can I make these burgers in advance?
You can make and reheat these burgers, but they lose some of their star quality when reheated for burgers. They are so quick and easy I’d recommend making them fresh. However, if you have leftover cooked mushrooms, they make a fabulous breakfast sliced, warmed, and served with poached eggs and toast.
Portobello Mushroom Burgers Recipe
Portobello Mushroom Burger
for the mushrooms:
- 4 Tbsp balsamic vinegar
- 2 Tbsp extra-virgin olive oil
- 1 tsp dried oregano
- 1 Tbsp light soy sauce
- 1-2 cloves garlic, crushed
- 4 large Portobello mushrooms, stems removed
- oil, for cooking
for the potato wedges:
- 3 large baking potatoes
- 1.5 Tbsp oil
- 1 tsp dried oregano
- ½ tsp paprika
- sea salt and black pepper
- 4 brioche hamburger buns
- 1 large tomato, sliced
- salad leaves
- sliced Swiss cheese
- ketchup and Dijon mustard
- quick pickled red onion slices
for the spicy sauce:
- ½ cup mayonnaise
- 2 -3 tsp harissa paste
- MAKE THE MARINADE: Whisk the balsamic, olive oil, oregano, soy sauce and garlic in a small bowl. Dip the smooth side of each mushroom in the marinade, rubbing to cover evenly, then place mushrooms gill side up in a flat dish and pour over the marinade. Set aside.
- COOK THE POTATO WEDGES: Heat the oven to 200°C / 400°F / Gas 6 and line an oven tray with baking parchment paper. Cut the potatoes into thick wedges and transfer them to the prepared tray. Drizzle over the oil and toss well to combine. Sprinkle over the oregano and paprika, then roast in the oven for 30-40 minutes until golden and tender. Season generously with salt and pepper, and keep warm.
- PREPARE FILLINGS: While the potatoes are cooking, prepare your ingredients, slicing vegetables, buns, cheese etc. and stirring together the mayonnaise and harissa to make the spicy sauce.
- COOK THE BURGERS: When the wedges have been in the oven for 20-25 minutes, cook the portobello burgers. First, heat a little oil in a large skillet or non-stick pan over medium-high heat, then cook the mushrooms for 4-5 minutes on each side until deeply golden brown. Use a pastry brush to brush with the leftover marinade as you go. Next, heat the oven grill/broiler to high.
- ASSEMBLE: When your mushrooms are cooked and a rich, deep brown, lay a slice of Swiss cheese on top of each and place under the hot grill until the cheese has melted. Transfer the burgers briefly to a plate lined with a paper towel and gently press them down to drain some excess juices. Finally, assemble your mushroom burgers, topping them with tomato slices and your favourite condiments. Serve hot with the wedges and spicy sauce.
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