Grilled Portobello Lettuce Burgers (Plant Paradox friendly, vegan, gluten-free)

Do you know what I’ve missed the most from eating predominately lectin-free? Burgers. And I’m not even talking about beef burgers, I’m talking about really good veggie burgers. In fact, I’ve tried the “Impossible Burger” twice now, imagining that it’ll satisfy my deepest burger cravings, but now I realize that maybe I don’t even miss the texture of actual meat. What I do miss, however, is the mouth-watering experience of holding a burger in hand, loaded with toppings, finished with soft, pillowy buns that hold it all together.

To come clean to you, I’ve been quite apprehensive about using lettuce as a bun for a while now. I don’t know, it’s just that crisp, watery lettuce is so far from what I imagine a burger should be. Although, given enough time without burgers, I caved and decided to use lettuce as my wrap. And y’all, it is so good.


Why did I doubt the abilities of lettuce for so long?! This wrap came out deeply satisfying and it really did hit that “burger craving.”

Any burger won’t be satisfying without proper seasoning though, which is why we concocted a tangy & savory marinate for our portobello mushroom caps. The base of our marinade comes from extra virgin olive oil (surprise surprise), which is mixed with Worcestershire sauce, tamari sauce, dijon mustard, and balsamic vinegar.

The tamari & Worcestershire sauces add complex, umami flavors, which is crucial to achieving ultimate satisfaction as those are flavors naturally found in meats. Balsamic vinegar is important as it’s acidic, and acid creates saliva, and saliva starts breaking down the food in the mouth before it ever reaches the stomach. While that may not sound very appealing, it’s acids that create that “mouth-watering” effect. The dijon mustard has two roles: 1. it adds kick to the marinade and 2. mustard is an emulsifier, meaning it allows for water and oil to cohere together in a state of suspended animation. Without mustard, the water from the tamari & Worcestershire sauces would not mix with the olive oil.


Cooking these caps doesn’t get much easier, plus it only takes about 6 minutes in total! The obvious cooking choice is to grill the mushrooms because, duh, everyone loves grill marks on their burger. However, grilling has another benefit that’s often overlooked: the grates on an outside grill or the indents on a grill-pan allow liquids to fall away from the food as it cooks. In regular pan or skillet, on the other hand, moisture from the food is held against itself, which essentially steams it until all of the moisture has evaporated. Because mushrooms – as well as beef burgers, if you think about it – create a lot of moisture during the cooking process, it’s important that it stays away from the mushrooms so that they have time to develop a deep, dry-cooked flavor – as well as grill marks.

If you don’t have a grill pan or outdoor grill, what you can do is crank your broiler to high and place the mushrooms directly on a rack in the oven as close to the broiler as possible. To catch the drippings, place a cookie sheet on the rack beneath the mushrooms. They may take a minute or two extra to cook per side, but this method has direct heat and prevents moisture from cluttering against the mushrooms.


Oh, and remember that marinade from before? Well, there’s definitely gonna be excess left over once you extract the mushrooms. Being that the marinade is packed with flavor, why not turn it into a sauce! How you ask? Ahh, simply, think of the most ubiquitous burger topping of all time – ketchup. To make the sauce thick enough to stay on the burgers, mix one tablespoon of the leftover marinade with two tablespoons of homemade, sugar-free ketchup for an actual finger-licking good sauce.

No but seriously, this sauce will get every where. You didn’t actually think that lettuce had the ability to contain sauce the same a bun does, did you? Good riddance.

All in all, this burger is:

  • Packed with complex umami flavors
  • Juicy
  • Comforting
  • Easy to make

If you like what your taste buds are tellin’ ya, leave behind a nice rating, share your thoughts with us in the comments, or show us your creations by tagging @noeggsorham on Instagram.

Go Forth & Devour,
Kim & Ryan


Grilled Portobello Lettuce Burgers (Plant Paradox friendly, vegan, gluten-free)

  • Servings: Two
  • Difficulty: Easy
  • Print

Umami portobello burgers wrapped in a lettuce bun, topped with sweet & tangy sauce, creamy guac, and crisp red onions.


Portobello Caps

  • 2 large portobello caps, de-stemmed (the flatter, the better)
  • 2 tbsp olive oil
  • 2 tsp vegan Worcestershire sauce
  • 2 tsp tamari
  • 1 tsp dijon mustard
  • 1 tsp balsamic vinegar

Simple Guacamole

  • 1 small ripe avocado
  • squeeze of lemon or lime
  • pinch of salt


  • 4 large lettuce leaves (we find green leaf lettuce to work best here)
  • thinly sliced red onion rings
  • cooked mushrooms
  • guacamole
  • 2 tbsp homemade ketchup + 1 tbsp leftover marinade


  1. In a small bowl, combine olive oil, Worcestershire, tamari, mustard, and balsamic vinegar. Whisk together with a fork or whisk.
  2. Place portobello caps on a plate and pour the Worcestershire marinade on top of the gill side of the mushrooms. Rub it in all the way around until they’re coated. Let ’em sit at room temperature for 15-20 minutes.
  3. While the ‘shrooms marinate, slice your onion and combine all of the guac ingredients in a bowl and mash together with a fork. Set aside.
  4. During the last 5 minutes of marination, heat a grill-pan over medium heat. Allow to heat completely before cooking mushrooms. (If using an outdoor grill, prep it accordingly – I don’t have one, so I don’t know how long to heat it up for.)
  5. Brush excess marinade off of the mushrooms, spray grill-pan with a light coat of non-stick spray or a brush of olive oil, and place on the burgers.
  6. Allow them to cook for 3-4 minutes per side, or until light grill marks form on each side. Be sure not to overcook them as they will shrink significantly and become increasingly tough.
  7. While burgers cook, mix one tablespoon of leftover marinade with two tablespoons of ketchup.
  8. Transfer burgers to a large leaf of lettuce each and top with guacamole, red onion slices, and sauce. Fold up the sides of the leaf then top with a second leaf of lettuce and fold the sides down towards the bottom.
  9. Nail together the sandwich with a toothpick or skewer to help keep everything in place. Enjoy while fresh!