Delicious fried Portobello Mushroom burger in a brioche bun with swiss cheese, rocket and garlic mayo sauce. It’s so satisfyingly good!

Burgers and Mushrooms

I crave for burgers much more than I really should and I have ever come across a mushroom I didn’t like. This is why mushroom burgers are incredibly appealing to me. After all, as they do say, mushrooms are ‘meat for vegetarians’.

But no one in our household is a vegetarian. I mean, I wish I was one because I love animals but old habits are hard to break. My mum was feeding me meat since I was in her womb!

No one loves meat more than my husband Tomasi. When I told him I was making mushroom burgers he asked me if I was going to add bacon and when I said no he became disinterested.

I wasn’t disheartened by Tomasi’s reaction as I know my him very well. He ain’t gonna turn down a burger with brioche bun, crispy fried mushroom, swiss cheese and garlic mayo sauce.

Of course, Tomasi ended up loving this fried portobello burger. So, regardless if you are a vegetarian or a meat lover, this tasty burger is guaranteed to impress you!

Not only is it lip-smacking delicious it will also leave you feeling full and satisfied thanks to the meaty portobello mushroom. It’s almost like portobellos were created for burgers, they’re the perfect size and shape.

Mushrooms 101 – Buying, storing and cleaning

Mushrooms can be a little tricky to work with for beginners so here is a quick 101 on ‘shrooms’.

Only purchase mushrooms 2 days in advance from when you want to use them as they do not keep well.

Closed cap mushrooms are generally fresher and mild tasting. You can see if the cap of the mushroom by turning it upside down if it’s closed you cannot see the gills. This work for the small and medium-size mushroom varieties but not the large ones such as portobello.

When choosing portobello or larger size mushrooms, select ones that are not spotty or slimy. They should look plump and firm.

If the mushrooms are not prepackaged, store them in a paper bag or wrap them loosely in a tea towel and place it in the fridge. Avoid leaving mushrooms in a closed plastic bag with no air as it’ll go bad quickly.

Do you have an overwhelming urge to scrub your mushrooms clean under the water? After all, they grow near the ground and you can see some dirt on it.

If your answer is yes I don’t blame you, as I do too! BUT DON’T as mushrooms are like sponges, they absorb everything around them. So giving them a water bath is not the best idea unless you want watery tasteless mushrooms.

Having previous work experience in a commercial kitchen I learned how to properly prepare mushrooms. We either had to peel the top layer of the mushroom or use a damp paper towel to gently clean each one.

Depending on what I am cooking I use either method. With portobello mushrooms, I peel it as it’s not as labour intensive as peeling several small ones.

Ingredients for Fried Portobello Mushroom Burger

FOR THE GARLIC MAYO SAUCE

Portobello mushroom – Try and select mushrooms that are slightly bigger than the burger bun. As we are frying the portobello there is no need to remove the gills, to clean it we will be peeling of the skin from the cap. Any variety of large mushroom can be used if portobellos aren’t available such as ‘flat mushrooms’.

Brioche buns – The soft, sweet and buttery buns work really well with the fried mushroom and swiss cheese. If you are not a fan of brioche you can swap it with your favourite buns.

Swiss cheese – The nutty, sweet and mild flavour of Swiss cheese in this burger complements the fried mushroom and brioche. You can swap Swiss cheese for your favourite slice of cheese.

Panko bread crumbs is a Japanese breadcrumb. Panko is lighter and flakier than Western-style breadcrumbs, it absorbs less oil and makes food crispier in texture. You can usually find Panko in the international section in supermarkets or in Asian specialty shops.

Parmesan cheese – Use the grated parmesan cheese you find on the supermarket shelf (not in a fridge area).

Baby rocket (Arugula) – Rocket has a peppery and bitter taste. Due to its bitterness, rocket may not be suited to everyone’s taste. A good alternative is baby spinach as it has a more neutral taste.

Here are some more delicious mushroom recipes to try:

How to make Fried Portobello Mushroom Burger

Step-by-step guide with photos

Make the garlic mayonnaise sauce

In a mini food processor add in the garlic and pulse until finely chopped, add in the mayonnaise and lemon and pulse a few times until combined. Transfer the to a small bowl, add in salt, pepper and stir to combine. Set aside for the flavours to develop.

Prepare the portobello mushrooms

Turn the portobellos upside down, using a small sharp knife cut off the stems leaving just the caps. Using your fingers gently pull off a thin layer of skin from the cap starting from the outer edges to the centre of the mushroom.

Bread the portobellos

Use 3 separate bowls to bread the portobellos. One bowl for flour, one bowl for a lightly beaten egg, one bowl for the breading mix (combine panko, salt, pepper, paprika and garlic powder and mix well)

To ensure no excess oil will seep into the portobello whilst frying take the time to cover the entire portobello (including under the caps) in all 3 breading steps.

STEP 1: Cover the entire portobello in flour and shake off any excess STEP 2: Cover the entire portobello into the egg making sure there are no dry spots STEP 3: cover the entire portobello with the breading mix.

Fry the portobello mushrooms

If using a deep fryer, heat up oil to 180°C (356°F) and cook mushroom for 3 to 4 minutes on each side. To shallow fry use a medium size fry pan and pour enough oil to cover the mushroom halfway. Heat the oil on medium heat, the oil will be ready when to use when it bubbles when a small piece of bread is added. Cook the mushroom for 3 to 4 minutes on each side. Make sure the oil is not too hot or it will burn the crumbs without cooking the mushroom.

Place the mushrooms on a cooling rack and add a slice of Swiss cheese on top, the residual heat from the mushrooms will slightly melt the cheese.

Load up the burger

Grill the insides of the burger buns on high heat for a couple of minutes or until toasted.

Starting at the bun base, place the rocket leaves, the portobello mushroom, swiss cheese, the garlic mayo sauce and the burger lid.

I’ve used a third-party application to calculate the calories and nutritional information, so please use this as an approximate guide only.

Cooking measurements are in Australian standard spoon and cup measurements. For specific details and conversions, visit our Australian Cooking Measurements page.

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Cheers – Cat T