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Loaded Zesty Portobello Burger

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Loaded Zesty Portobello Burger has so much flavor in every bite, starting with the easy mushroom marinade. Grill the bun and toppings for the perfect burger. A little heat, a lot of textures, and a ton of flavor in this burger even meat lovers will crave

This post and recipe card updated May 18, 2020
close up picture of finished portobello burger on parchment paper with a beer in the background

Growing up, I never really ate mushrooms. I honestly don’t recall my parents making them; and if they did, the mushrooms were mixed into a dish.

While there are lots of mushroom varieties, I keep it simple. I prefer white button mushrooms for my Easy Pan Fried Mushrooms and my Spinach and Bacon Stuffed Mushrooms. But most of the time I use baby portobellos.

I’ve always been a huge fan of burgers, and at restaurants, I usually start my menu search in the burger section. I don’t make burgers at home very often, so when I do I make them special. My Venison Cheesesteak Sloppy Joes are fabulous, and one of the most popular recipes on the blog.

Although I love the traditional burger, sometimes I’m craving something lighter. So this was the perfect opportunity to create my Loaded Zesty Portobello Burgers

WHY THIS RECIPE WORKS
  • Vegetarians and meat eaters alike will love the meaty texture of the portobellos
  • You can easily turn the heat up or down with the jalapenos
  • The creamy avocado mash is the perfect topping
close up picture of finished portobello burger with the top bun on the side on parchment paper with a beer in the background

I always scoffed at people who said that portobellos “taste like meat”. But when you cook them right and add great burger toppings, you almost forget you’re eating mushrooms. Almost.

PREPARING THE MUSHROOMS

You can find portobello mushroom caps in every grocery store. Most stores sell them in packages of 2, but some stores have them in bulk containers so you can pick exactly what you need.

Mushrooms have no flavor on their own, so a bold marinade is key.

  • I’m not sure exactly what’s in Worcestershire sauce, but it’s one of those ingredients that you miss when you don’t add it
  • Use a good quality Balsamic Vinegar. Grocery stores have upped their game recently, with a wide variety of good options
  • You can’t have a good marinade without fresh garlic
  • You always need a little bit of oil, and I love the silky taste of Avocado Oil
LOADED ZESTY PORTOBELLO BURGER TOPPINGS

Fresh jalapenos have a lot of heat, so I grill them to tone down that spice. I grill them whole and then slice them in half, and the seeds scrape out easily.

I prefer to use red onion, but you could certainly substitute yellow. Grilling the onions makes them even sweeter.

I add baby spinach and fresh sliced tomatoes. You can substitute leaf or iceberg lettuce for the spinach if you prefer.

Avocado is one of my favorite burger toppings. I added sliced avocado the first time, but it kept sliding off the sandwich. So instead I roughly smash the avocado, and top it that way instead.

Mayonnaise is the final, optional touch. About a year ago I discovered Duke’s Mayonnaise, and I’m obsessed and use it all the time. But when I want to lighten it up a little, I’ll use Avocado Oil Mayo.

close up picture of finished portobello burger on parchment paper with a beer in the background
STEP BY STEP INSTRUCTIONS

Add the marinade ingredients in a container. Wipe off any excess dirt from the mushrooms with a towel, and remove the stems. Place the mushrooms, cap-side down, in the marinade for 15 minutes.

overhead process shot: portobello mushrooms in marinade in a glass container

While mushrooms marinate, preheat the grill to 350 degrees and spray the grates with cooking spray. Place jalapenos and red onions on the grill.

Process shot: jalapenos and red onions on the grill

Grill vegetables for 10 minutes, turning once halfway through. Remove vegetables. Cut the stem from the jalapenos, and slice lengthwise in half. Scoop out the seeds and slice each half into half again.

Place mushrooms, cap-side down, onto the grill. Grill mushrooms for 3 minutes per side, turning once halfway through.

process shot: mushrooms on the grill

Remove mushrooms and slice lengthwise into strips.

Spray burger buns lightly with cooking spray and place on the grill for 2 minutes, until lightly toasted.

Assemble burgers.

overhead shot of burger ingredients on a black board

Spread a little mayo on each bun. Layer with baby spinach, tomato, onion, avocado mash, mushrooms, and jalapeno slices.

overhead picture of finished portobello burger on parchment paper
FREQUENTLY ASKED QUESTIONS

How about leftovers? I don’t recommend reheating cooked mushrooms, as they get a kind of rubbery texture. And besides, they’re so quick and easy to marinate, you can just make them fresh.

Can I leave the mushroom caps whole? It really depends on the size. If the caps are huge and bigger than the burger bun I’ll slice them before I marinate; otherwise, I’ll leave them whole.

Can I roast the mushrooms instead of grilling? Absolutely but then I recommend not slicing the mushrooms until after they cook. Otherwise the pieces will shrink.

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Loaded Zesty Portobello Burger - Karyl's Kulinary Krusade

Loaded Zesty Portobello Burger

Yield: 2 burgers
Prep Time: 30 minutes
Cook Time: 15 minutes
Total Time: 45 minutes

Loaded Zesty Portobello Burger has so much flavor in every bite, starting with the easy mushroom marinade. Grill the bun and toppings for the perfect burger. A little heat, a lot of textures, and a ton of flavor in this burger even meat lovers will crave

Ingredients

  • 2 hamburger buns
  • 2 large portobello mushroom caps

MUSHROOM MARINADE

  • 1/4 cup high quality balsamic vinegar
  • 1 Tablespoon avocado oil
  • 4 cloves raw garlic, roughly chopped
  • 1 Tablespoon Worcestershire sauce

TOPPINGS

  • 2 jalapenos, whole
  • 1 medium avocado
  • 4 slices tomato
  • 1/2 cup red onions, sliced into 1/2" pieces
  • 1/2 cup baby spinach, rinsed and dried
  • 2 Tablespoons avocado oil mayo

Instructions

  1. Wipe mushroom caps clean and remove stems. Cut into 3/4" slices
  2. Combine balsamic vinegar, avocado oil, Worcestershire sauce and garlic in a bowl. Add mushrooms to marinade, and let rest for 15 minutes.
  3. PREPARE TOPPINGS WHILE MUSHROOMS MARINATE.
  4. Heat grill or grill pan to medium-high heat, and spray with nonstick spray. Add jalapenos and onions. Both will take about 10 minutes to cook.
  5. Turn jalapenos every 2-3 minutes so all sides get charred. Turn onions after 5 minutes.
  6. Remove onions and set aside.
  7. Remove jalapenos and allow to cool for a couple of minutes. Cut off ends, slice lengthwise into strips, and scrape out seeds.
  8. Place sliced mushrooms on grill and cook for 2-3 minutes per side. Remove mushrooms and set aside.
  9. Turn grill heat to medium-low, and place burger buns face side down on grill. Toast for about 2 minutes, and remove from heat.
  10. Peel and seed avocado. Cut into large dice, and mash with a fork.
  11. Lay buns toasted side up on platter, and add mayo. Add baby spinach, tomato, portobellos, avocado mash, and jalapeno slices. Finish burgers with top buns

Notes

Slice the mushroom caps or leave them whole? It really depends on the size. If the caps are huge I’ll slice them before I marinate; otherwise, I’ll leave them whole.

Mushrooms have no flavor on their own, so a bold marinade is key.

  • I’m not sure exactly what’s in Worchestershire sauce, but it’s one of those ingredients that you miss when you don’t add it
  • Use a good quality Balsamic Vinegar. Grocery stores have upped their game recently, with a wide variety of good options
  • You can’t have a good marinade without minced garlic
  • You always need a little bit of oil, and I love the silky taste of Avocado Oil

FREQUENTLY ASKED QUESTIONS

What kind of bun should I use? I like to use a traditional Sesame Burger Bun, but use your favorite. You could even make it into a wrap with a tortilla.

Can I leave the mushroom caps whole? It really depends on the size. If the caps are huge and bigger than the burger bun I’ll slice them before I marinate; otherwise, I’ll leave them whole.

Should I slice the portobellos before or after marinating? That’s up to you. The mushrooms will absorb the marinade all the way through if you slice first, but I prefer to marinate the caps whole.

Can I roast the mushrooms instead of grilling? Absolutely but then I recommend not slicing the mushrooms until after they cook. Otherwise the pieces will shrink.

Nutrition Information:
Yield: 2 Serving Size: 1
Amount Per Serving: Calories: 735Total Fat: 57gSaturated Fat: 8gTrans Fat: 0gUnsaturated Fat: 46gCholesterol: 3mgSodium: 384mgCarbohydrates: 51gFiber: 12gSugar: 14gProtein: 10g

Nutrient values are estimates only. Variations may occur due to product availability and food preparation. Nutrition may vary based on methods of preparation, origin and freshness of ingredients, etc

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Noreen

Thursday 17th of January 2019

It doesn’t say when to put the mushrooms on the grill so I started them with the veggies. Easy and Delish!

Karyl

Monday 28th of January 2019

Oh I'll need to update that Noreen, thanks for catching it. And I'm so glad you liked it!

Claire | The Simple, Sweet Life

Monday 26th of February 2018

Portobello mushrooms are my absolute favorite! I bet this is absolutely delicious!

Karyl

Thursday 1st of March 2018

Yes, this burger is fantastic Claire! Marinating the mushrooms makes such a big difference

Elena

Monday 26th of February 2018

Oh my! You won my heart with this burger Karyl! Can't wait to try this recipe :)

Karyl

Thursday 1st of March 2018

Awww thanks Elena!! I hope you love it as much as I do

Ashima

Monday 26th of February 2018

I am always looking for different vegetarian burger recipes! Your's looks so tasty and easy to make. I love the combinations.. mushroom, spinach, onion, avocado and jalapeño for that added heat!

Thanks for sharing

Karyl

Thursday 1st of March 2018

Thanks Ashima! Yes, it really is super easy to make and the marinade makes all the difference in the flavor of the mushrooms

Marissa Zurfluh

Monday 26th of February 2018

I love portabella mushrooms. This is an awesome replacement for fatty beef.

Karyl

Thursday 1st of March 2018

Yes it is Marissa! Thanks for stopping by

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