Grilled vegetarian portobello burgers

I used to think a mushroom cap could never stand in for a burger patty. Then one hot July evening, our air conditioner gave up, nobody wanted the oven on, and I had four portobellos sitting in the fridge doing nothing.

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• Portobello Mushroom Burger

That night I made my first portobello mushroom burger, and Donald ate his standing at the counter before I even sat down.

Here's the thing about this one. The mushrooms cook in a grill pan in about 10 minutes, the avocado sauce takes two minutes to stir together, and the whole dinner is done in half an hour.

Alex was 11 the first time I served these, and he asked where the meat was. By the second bite he stopped asking. Sarah picks the roasted red peppers off hers, which is fine by me, and I get to eat them.

If your family is more of a beef crowd, I get it. Some nights we go with my grilled ground beef smash burgers instead, and honestly the avocado sauce below works on those too.

Why You Will Like This Portobello Mushroom Burger

• Dinner is on the table in 30 minutes total, start to finish
• You need one skillet or grill pan, so cleanup is quick
• The mushrooms turn juicy and a little smoky, with real bite to them
• The cool avocado and yogurt sauce balances the warm mushroom perfectly
• Everything can be made without a grill, which matters when you live in an apartment
• It works for vegetarians and adapts to vegan with one small swap

What You Need For A Portobello Mushroom Burger

Nothing fancy here. I buy most of this at the corner market on my walk home.

For the burgers:

• 4 medium portobello mushrooms, stems removed
• 1 medium onion, cut into half inch slices
• 3 tablespoons olive oil
• ¾ teaspoon salt, divided
• ½ teaspoon freshly ground black pepper, divided

For the avocado sauce:

• 1 ripe avocado, peeled and sliced
• 2 tablespoons low fat yogurt
• ½ teaspoon garlic, minced

Serving:

• 4 hamburger buns, lightly toasted
• 4 jarred roasted red peppers (optional)
• Lettuce leaves (optional)
• Tomato slices (optional)

A quick note on the mushrooms. Pick caps that feel firm and dry, not slippery. If the gills underneath look wet and dark, put them back.

For the yogurt, plain works best. I tried it once with vanilla yogurt because that was all I had, and let me tell you, that was a mistake I only made one time.

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How To Make A Portobello Mushroom Burger Step By Step

Season The Mushrooms And Onion

1. Wipe the mushroom caps clean with a damp paper towel. Do not run them under the faucet, because they soak up water like a sponge.
2. Brush both sides of the mushrooms and the onion slices lightly with olive oil.
3. Sprinkle them with ½ teaspoon of the salt and ¼ teaspoon of the pepper. Keep the rest for the sauce.

Cook The Mushrooms

4. Heat a large skillet or grill pan over medium heat until it is properly hot. Give it a couple of minutes.
5. Lay the mushrooms in the pan, gill side up, and cook 8 to 10 minutes, turning once. They are ready when a fork slides in with no resistance.
6. Move them to a plate, cavity side up, and cover loosely with a clean kitchen towel to hold the heat.

Do not press down on them while they cook. I did that for years thinking I was helping, and all I did was squeeze out the juice.

Brown The Onion Slices

7. In the same pan, cook the onion slices about 8 minutes, turning now and then, until they are golden at the edges.

Stir Together The Avocado Sauce

8. Mash the avocado in a small bowl with a fork. Leave it a little chunky.
9. Stir in the yogurt, the minced garlic, and the remaining salt and pepper. Taste it. Add more garlic if you love garlic the way Donald does.

Build The Burger

10. Toast the buns lightly. This step is not optional in my kitchen, because a soft bun under a juicy mushroom turns sad fast.
11. Spread the avocado sauce on the bottom bun, add the mushroom cavity side up, then pile on the onions, roasted red peppers, lettuce, and tomato.
12. Put the top bun on and press gently. Eat it right away while it is warm.

Storage And Reheating Tips

Cooked mushrooms keep in the fridge for up to 3 days in an airtight container. Store them separately from the buns and the sauce.

The avocado sauce is best the day you make it. Press plastic wrap right onto the surface and it will hold overnight without turning brown.

To reheat, warm the mushrooms in a dry skillet over medium heat for 2 to 3 minutes per side. The microwave works, but the texture goes rubbery, so I skip it.

I would not freeze these. I tested it once out of curiosity and ended up with something watery and gray that nobody wanted.

Ways To Change Up Your Portobello Mushroom Burger

Want to know the swap my kids ask for most? Melted provolone laid over the mushroom during the last minute in the pan.

• Make it vegan. Skip the yogurt and use a plain soy or coconut yogurt instead. Nobody at my table noticed.
• Add heat. A pinch of chili flakes in the avocado sauce wakes the whole thing up.
• Change the sauce. My homemade tzatziki sauce is lovely here on a hot night.
• Go bunless. Serve the mushroom over a pile of greens with the sauce spooned on top.
• Marinate first. Ten minutes in olive oil, balsamic vinegar, and garlic gives the mushrooms real depth.

One thing to watch out for. If your pan is not hot enough when the mushrooms go in, they steam instead of browning, and you lose that lightly charred edge that makes this taste like a real burger.

Questions I Get About This Portobello Mushroom Burger

How Do You Keep Portobello Mushroom Burgers From Getting Soggy?

Never wash the caps under running water, and scrape out the dark gills with a spoon if they look very wet. Cook them in a hot pan rather than a warm one, and always toast the bun. Those three habits fixed the problem for me completely.

How Long Should Portobello Mushrooms Cook On The Grill?

About 8 to 10 minutes total over medium heat, turning once halfway through. Thicker caps might need a minute or two more. You want them tender all the way through, not crisp.

What Toppings Go Well With A Portobello Mushroom Burger?

Roasted red peppers, sliced tomato, crisp lettuce, and caramelized onions are what I reach for. Melted provolone or goat cheese works beautifully. Sarah likes hers with pickles, which sounds odd until you try it.

How Can You Make A Portobello Mushroom And Avocado Burger Vegan?

Swap the low fat yogurt for a plain non dairy yogurt made from soy, coconut, or almond. Check that your buns contain no eggs or butter, and you are all set. The taste barely changes.

Recipes You May Like

• Garlic Parmesan Fries because burgers deserve fries, and these come out crisp every time.
• Creamy Macaroni Salad For Your Next BBQ which I make ahead and pull straight from the fridge.
• Creamy Cucumber Salad With A Sweet Twist for something cool and crunchy alongside.

Looking for another meatless dinner during the week? My crispy baked sesame tofu gets requested almost as often as this one.

My Final Thoughts On This Portobello Mushroom Burger

Season your mushrooms, cook them in a properly hot pan, mash up that avocado sauce, and toast the buns. That is really all there is to it.

I love this recipe because it proves dinner does not have to be complicated to feel like a treat. It costs less than takeout, it uses real ingredients, and it comes together faster than delivery would arrive at our door.

Give this portobello mushroom burger a try this week and tell me how it went in the comments. I read every one.