This vegan, gluten-free, and grain-free roasted vegetable sandwich with avocado-basil aioli is packed to its mushroomy edges with goodness.
Juicy.
Stacked.
Roasted.
Garlicky.
Saucy.
Colorful.
Sink-your-teeth-in tasty.
This roasted vegetable sandwich feels rather burger-like in look and heartiness. But don't be fooled. It's nothing more nor less than a stack of roasted vegetables slathered with a creamy avocado-basil aioli and jazzed up with a frilly piece of butter lettuce. Roasted portobello caps serve as buns, and roasted zucchini, tomatoes, red onion, and red peppers are piled high within to yield layers of flavor and texture. The "buns" are slathered with an avocado-basil aioli, which is simply avocado, basil, garlic, lemon juice, and a pinch of salt that have been tossed into a food processor and blended into a creamy sauce.
The great part about this sandwich is that all of the veggies get roasted in the oven at the same time, portobello caps included. This means that you can whip together the aioli, wash your prettiest lettuce leaves, and set the table all while the vegetables are roasting. Once the veggies are ready, you'll slather the aioli on the portobello buns, toss on some lettuce, and pile on the zucchini, tomatoes, onions, and red peppers.
Stick a toothpick in it, it's done.
📖 Recipe
Roasted Vegetable Sandwich with Avocado-Basil Aioli
Ingredients
For the Buns
- 4 large portobello mushroom caps
- sea salt
- black pepper
For the Roasted Vegetables
- 1 vine-ripe tomato, sliced into ⅓-inch-thick rounds
- ½ jar roasted red peppers
- 1 medium zucchini, ends trimmed, halved, and sliced lengthwise
- 1 small red onion, peeled and sliced into ½-inch-thick rounds
- ½ jar roasted red peppers, sliced into 2-inch strips
For the Avocado-Basil Aioli
- 1 avocado, pitted
- ⅓ cup fresh basil leaves
- 1 tablespoon fresh lemon juice
- 1 garlic clove, peeled
- ¼ teaspoon sea salt or to taste
For Garnishing
- 4 butter lettuce or romaine leaves, washed and roughly torn
Instructions
- Preheat oven to 400F.
- Clean, de-stem, and scoop out the gills of the portobello mushrooms. Place all four, gill-side-down, on a large baking sheet lined with parchment pepper. Sprinkle with the tops with salt and pepper and roast for 20-25 minutes or until tender.
- At the same time, add the tomatoes, zucchini, and red onion to a pan lined with parchment paper, and sprinkle with sea salt and black pepper. Bake alongside the mushrooms for 20-25 minutes or until tender, flip halfway through and season other side of veggies with black pepper and sea salt.
For the Avocado-Basil Mayo
- Add the avocado flesh, basil leaves, garlic, lemon juice, and sea salt to a food processor. Process for 2-3 minutes or until smooth, stopping as needed to scrape down the sides.
To Assemble
- Slather the gill-side of all 4 mushroom caps with the avocado-basil aioli. On two of the portobello caps, layer the lettuce leaves, zucchini, tomatoes, red onion, and roasted red peppers. Top with the other portobello caps, and serve.
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Emjay says
That looks delicious. I'm a carb ho, so I'll be putting that baby on a bun!
Ashley says
Haha, I love this comment. I'm also a huge carb lover, so I hear you on the bun. I would throw a portobello or two into the bun with the other veggies too. I hope you enjoy it, Emjay!
Celeste Jackson says
My mouth is watering looking at the photo! I will be making this before the week is over. Love the fact that the vegetables get roasted all at the same time. Thank you!
Ashley says
Roasting all the vegetables at once really keeps this one simple and time-efficient. I hope you enjoy the recipe!
Kacey @ The Cookie Writer says
You have no idea how excited I am to try these!! I have some extra portobellos on hand and will need to make these ASAP!
Ashley says
I'm so glad you're excited about this recipe, Kacey! If you gave it a go, I hope you enjoyed it :)
Thalia @ butter and brioche says
I have to try this veggie sandwich recipe out - i am obsessed with the idea of using mushrooms as a burger bun base!
Ashley says
You have to try it, Thalia! It makes for a nice, light lunch, which is great for those days when there is too much to be done to risk a case of post-lunch sleepiness.
lynsey | lynseylovesfood says
oh i saw this on pinterest before i saw it hear and it had my love at first glance. love me a good stack of veggies. xo
Ashley says
Love at first glance -- I love it! Thanks so much, Lynsey!
Sandra says
Ahh, that looks amazing!
Ashley says
Thanks so much, Sandra!
Nala says
This looks amazing, I'm going to make it tonight! What's it like cold, would love to take it to work for lunch?
Ashley says
Hi, Nala! It's good cold too, you'll just want to make sure you prepare the avocado-basil aioli the same day that you're eating it since avocado browns and turns so quickly. I hope you enjoy it!