Roasted Veggie Sandwiches with Avocado Aioli

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These roasted vegetable sandwiches are jam-packed with hearty roasted broccoli, juicy bell peppers, and mushrooms, all slathered in a creamy, to-die-for avocado aioli. Easy, vegan, and perfect for lunch or dinner!

Roasted Vegetable Sandwich and chips on a plate with avocado aioli in the background.

We've all been there: you're at a restaurant with friends or family and the only thing on the menu you can eat is a boring veggie sandwich. Raw veggies, no dressing, and barely any flavor. Such a bummer, especially when you could've stayed home and made something way better, like a vegan cheesesteak or a vegan BLT. But don’t let that ruin veggie sandwiches for you. These roasted vegetable sandwiches are anything but boring.

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Ingredients You'll Need
How They're Made
Variations
Frequently Asked Questions
More Veggie Sandwiches
📖 Recipe
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A great sandwich isn’t just about the fillings — it’s also about the sauce. And these roasted vegetable sandwiches are all about the aioli. Avocado basil roasted garlic aioli, to be exact. SO GOOD. Truth be told, I really just came up with the sandwiches as a vehicle for the aioli, which I can eat by the spoonful. Putting it on a sandwich seemed more respectable. And since roasted broccoli, peppers, and mushrooms are delicious on their own, it all comes together to make a killer hot sandwich.

Ingredients You'll Need

Below you'll find a list of ingredients in this recipe, with notes and substitutions. Scroll all the way to the bottom of the post to see the full recipe, including the amount of each ingredient.

Ingredients for making Roasted Vegetable Sandwiches with labels.

Garlic. You'll need two whole bulbs of garlic. That's a lot! Well, yes, it is. But don't worry — roasted garlic has a super mild flavor. Don't be tempted to skimp here. Trust me!
Olive oil.
Avocados. Make sure they're ripe but not overripe. A little give when you press on the skin is good. Super soft is overripe, while rock hard isn't yet ripe. You can also pull out the stem — it should be green underneath.
Lemon juice. Fresh lemon juice is essential for the best aioli flavor.
Salt and pepper.
Fresh basil. Definitely use fresh. Dried won't work at all in this recipe.
Plant milk. Any unflavored and unsweetened non-dairy milk you normally like to drink is fine. Read my guide to non-dairy milks if you need help choosing one.
Mushrooms. I like these sandwiches with cremini mushrooms, but white button mushrooms also work.
Broccoli.
Red bell pepper.
Onion.
Sandwich rolls. You could also get fancy and cut a baguette into sections.
Red pepper flakes. These are optional. Just use them if you'd like a little heat.

How They're Made

Below is a detailed photo tutorial on how to make this dish. Scroll all the way down if you'd like to skip right to the recipe!

Get ready. Start by preheating your oven to 425°F.

Garlic bulbs coated in olive oil on foil in a baking dish.

Prepare the garlic. Cut the tops off of your bulbs, drizzle them in olive oil, and loosely wrap them in foil.

Two roasted garlic bulbs on foil in a baking dish.

Roast the garlic. Stick the foil-wrapped bulbs into the oven and roast them until the cloves are soft and browned.

Tips: If you don't like using foil, you can roast your garlic in a garlic roaster. Check out my guide on how to roast garlic if this is a new cooking technique to you.

Roasted mushrooms and bell pepper slices on a baking sheet.

Roast the vegetables. Arrange your mushrooms, sliced pepper, broccoli florets, and chopped onion on baking sheets, rub them with olive oil and sprinkle with salt and pepper.

Roasted broccoli and onion on a baking sheet.

Pop the baking sheets into the oven with the garlic, and roast the veggies until they're tender and browned in spots.

Avocadoes and roasted garlic in a food processor bowl.

Make the aioli. Place the avocado, lemon juice, salt and roasted garlic into a food processor bowl, and blend them first.

Avocado aioli in a food processor bowl with fresh basil leaves.

Blend in the basil next, and thin the mixture with some non-dairy milk.

Kitchen counter set with Roasted Vegetable Sandwich on a plate, surrounded by ingredients.

Assemble and serve. Slice open your sandwich rolls, slather them with the aioli, then stuff them with the veggies. If you've got some basil left, add that as well, along with a sprinkle of red pepper flakes if you'd like a little heat. Dig in!

Variations

Switch up the veggies. Try replacing any of the veggies with your favorites, like carrots, Brussels sprouts, zucchini, corn, or eggplant. Keep a close eye on them while they roast, since cook times can vary.
Add plant protein. Throw in some finely chopped baked tofu, like my savory lemon and herb baked tofu or Italian baked tofu. You could also include your favorite meat substitute, like seared vegan sausage or vegan chicken.
Add vegan cheese. Top your sandwiches with some sliced or shredded plant-based cheese, and optionally, pop them under a broiler for a few minutes to get it melty. You could also throw in some homemade vegan mozzarella or sprinkle the veggies with homemade vegan Parmesan cheese.

Section of a Roasted Vegetable Sandwich showing mushrooms, broccoli, peppers, and aioli.

Frequently Asked Questions

Can these sandwiches be made gluten-free?

Yes! Just use your favorite gluten-free rolls.

How can I reduce the fat and calories in this recipe?

Most of the fat comes from the aioli, so using less of that will lower both the fat and calories. You can also use less olive oil (cut it by no more than half) to lower the fat and calories, or a smaller roll to reduce the calories.

How long does the aioli keep?

That really depends on how fresh your avocados are — the fresher, the better! If they're just ripe, the aioli should stay green in a sealed container in the fridge for 2 or 3 days. If the avocados are already getting soft, the aioli will turn brown more quickly.

How should I store leftovers?

Leftover sandwiches will keep in sealed bags or airtight containers in the fridge for about two days, although the aioli may turn brown (it will still be edible, though). If the sandwiches are not yet assembled, the veggies will keep in airtight containers in the fridge for about three days. See the question above for storage details on the aioli.

More Veggie Sandwiches

Like this recipe? If so, please stop back and leave me a review and rating below if you try it! Also be sure to follow me on Facebook, Pinterest or Instagram, or subscribe to my newsletter for more recipes like this one!

📖 Recipe

Roasted Vegetable Sandwich on a plate with potato chips.

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5 from 1 vote

Roasted Vegetable Sandwiches with Garlic Avocado Aioli

Course Sandwich

Cuisine American

Prep Time 20

Cook Time 40

Total Time 1

Servings

Calories 514kcal

Author Alissa

Ingredients

For the Roasted Garlic Aioli

2 medium garlic bulbs
1 tablespoon olive oil
2 ripe avocados
3 tablespoons lemon juice
¾ teaspoon salt, or to taste
½ cup fresh basil leaves
3-4 tablespoons unsweetened non-dairy milk, as needed

For the Roasted Veggies

8 ounces cremini mushrooms, cleaned and sliced
1 medium broccoli crown, broken into florets
1 medium red bell pepper, sliced into strips
1 small onion, roughly chopped
2 tablespoons olive oil
½ teaspoon salt, or to taste
½ teaspoon black pepper, or to taste

For the Sandwiches

4 (6 inch) sandwich rolls, sliced open and optionally toasted
Fresh basil
Red pepper flakes, optional

US Customary - Metric

Instructions

To Roast the Garlic (for the Aioli)

Preheat the oven to 425ºF.
Use a sharp knife to cut the top off of each garlic bulb. Place each garlic bulb on a sheet of foil, then drizzle it with about ½ tablespoon of olive oil. Loosely close the foil to enclose the garlic.
Bake the garlic until the cloves are soft and lightly browned, about 30 minutes.
Open the foil and let them cool when done.

To Roast the Veggies

While the garlic roasts, line one large or 2 medium baking sheets with parchment paper.
Arrange the veggies on the baking sheet(s). Drizzle the mushrooms with 1 tablespoon of olive oil, and split the remaining tablespoon of oil evenly among the rest of the veggies. Gently rub the oil into the veggies to evenly coat them. Distribute them evenly on the baking sheet(s), then sprinkle them with salt and pepper.
Place the baking sheet(s) into the oven with the garlic, and roast the veggies until tender and browned in spots, about 20 minutes.

To Make the Aioli

Place the avocado, lemon juice, and salt into the bowl of a food processor fitted with an s-blade.
When the garlic is cool enough to handle, squeeze the bulbs to extract the roasted garlic, then add it to the food processor bowl.
Blend everything until smooth.
Add the basil and thin the mixture with non-dairy milk to your desired thickness. Blend again until smooth.
Taste-test and add more lemon juice and/or salt if you like.

To Assemble the Sandwiches

Slather the insides of the rolls with aioli, then stuff with roasted veggies and sprinkle with basil and optionally red pepper flakes.
Serve.

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