Portobello and Havarti Burgers with Caramelized Onions


We love portobello burgers. I like to use different herbs, vegetables, and cheeses to enhance the flavor of the mushroom. In this burger, I used Havarti cheese, caramelized onions, fresh basil and roasted garlic mayonnaise. It was light, flavorful and so delicious. You don’t always have to use meat to make a fantastic burger!

  • 1 sweet yellow onion, sliced thinly
  • 2 tsp olive oil
  • 4 large portobello mushrooms, stems removed and cleaned
  • 4 slices of Havarti cheese
  • 4 hamburger buns
  • Tomato slices
  • Fresh basil leaves

Heat olive oil in a skillet over medium heat. Add onions and saute until caramelized and tender – about 25-30 minutes, making sure to stir frequently. Season with sea salt to taste. Set aside when finished.

Mushroom Marinade:

  • 1/4 cup of balsamic vinegar
  • 1 tbsp olive oil
  • 1 tbsp fresh basil leaves, chopped finely
  • 1 clove of garlic, minced
  • Sea salt and fresh cracked pepper to taste

Marinate the mushrooms in a large zip lock bag for 15-20 minutes prior to cooking. Heat the same skillet, that the onions were cooked in, over medium heat. Once the skillet is hot, place the mushrooms in, top side up. Cook for 4-5 minutes then flip. Pile the caramelized onions onto the mushroom then place Havarti cheese and cook for an additional 4-5 minutes.

Roasted Garlic Mayonnaise:

  • 1 bulb of roasted garlic (see recipe here)
  • 2 tbsp mayonnaise
  • Sea salt and fresh cracked pepper to taste

Spread the garlic mayonnaise on each side of the bun, add the mushroom then top with tomato slices and basil. Enjoy!


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10 Responses to “Portobello and Havarti Burgers with Caramelized Onions”

  1. 1

    Paula — July 25, 2008 @ 7:26 pm

    Mmmm … extra m’s on this one. Your marinade and mayo sound terrific! My hubby loves caramelized onions on his “burgers”. The havarti/portobello combo sounds great! Your plating looks beautiful, too! Great looking tomatoes and basil!

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  2. 2

    Elle — July 25, 2008 @ 7:32 pm

    I *adore* portobello burgers. And adding Havarti is like icing on the cake.

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  3. 3

    gkbloodsugar — July 25, 2008 @ 8:46 pm

    You’re so right. Sometimes a big, juicy Portobello beats meat, hands down.

    The juice they let go into the bread is incredible ,isn’t it?

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  4. 4

    Nate-n-Annie — July 25, 2008 @ 9:37 pm

    I like the inclusion of basil leaves as a substitution for lettuce. Other leafy herbs could work as well.

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  5. 5

    ~Madeline~ — July 25, 2008 @ 11:27 pm

    I couldn’t agree with you more. While I love a good beef burger, a portobello or veggie burger can be just as satisfying. Yours looks delicious!

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  6. 6

    Jan — July 26, 2008 @ 12:22 am

    This looks and sounds delicious, I love caramelized onions on burgers.
    I like the sound of that garlic mayo, too.

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  7. 7

    Anonymous — July 26, 2008 @ 7:24 am

    I love portobello mushrooms…and this looks delicious!

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  8. 8

    Dhanggit — July 26, 2008 @ 9:18 am

    i have never tried making mushroom burgers yet..but when i saw all the ingredients you used..i salivated immediately!! this sounds a fantastic burger that could definitely kick the ass of MCdo LOL!!!! i love it

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  9. 9

    Kevin — July 26, 2008 @ 3:54 pm

    Mushrooms are one of my favorite things and a marinated portobello mushroom burger sounds really good!

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  10. 10

    Amy — February 20, 2012 @ 10:40 am

    LOVE TIS portobello burger. The marinade is perfect! I used Greek yogurt with a Parmesan spice added for the aoli. it was delicious and a little lower in calories. Thanks for this simple yet decadent recipe! Making it again tonight for meatless Mondays!

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