Grilled Veggie Sandwich with Pesto-Feta Mayo

These grilled veggie sandwiches are a weekly thing for us in the summer. They really are meant to be eaten when veggies are fresh (and cheap). Would this taste good in January? Probably. But it’d also cost you $15 per sandwich to grab all the out-of-season produce. Eat these sandwiches now. Eat them often. And then dream about them all winter long. That’s what we do.

What vegetables are on this grilled veggie sandwich? 

This sandwich was designed around what is coming out of the garden at any given moment. We make this in late summer, when we are drowning in eggplant, zucchini, peppers, and yellow squash. Throw in some red onion and mushrooms, and you’ll hit our usual veggie combo.

You can adjust the veggies of this sandwich all you want. Don’t like mushrooms? Leave ’em out. Only have green peppers? Cool. Want to add tomato slices? Sweet. If a veggie can be grilled, it can go on this sandwich.

Grilled Veggie Sandwich with Pesto-Feta Mayo

Tell me about this pesto-feta mayo!

A grilled veggie sandwich might seem like kind of a snoozefest, and that’s where this amazing Pesto-Feta Mayo comes in. This stuff is so good, my husband was literally eating it with a spoon while I was photographing this sandwich. It doesn’t overpower the flavor of the veggies—it just adds a nice, rich, tangy flavor and some cool, creamy texture.

Promise me you won’t skip the mayo. Even if you want to use vegan mayo and tofu or almond feta and vegan pesto, you have to make this mayo. Pinkie swear it. Right now. I’m extending my pinkie finger out, are you? You better be. (Psst: Need a plant-based version? Try this vegan sandwich instead.)

How to make a grilled veggie sandwich

  1. Whisk up the mayo and stash it in the fridge. This will let it chill and give the flavors time to meld. 
  2. If you’re using eggplant, the next step is to salt it to pull out some of the moisture and bitterness. Spread the eggplant out on a clean dish towel and sprinkle with salt. Let it sit for 10-15 minutes while you cut up the rest of the vegetables.
  3. Rinse the eggplant well with cool water to remove the salt and pat it dry. Preheat the grill.
  4. Toss the veggies (minus the mushrooms) with olive oil and oregano until everything is coated, and dump them in a grill basket.
  5. Brush the mushroom caps with oil on both sides.
  6. Place the grill basket and the mushroom caps on the grill grates. The mushrooms will need around 4 minutes per side, while the veggies in the basket will need about 10 minutes and frequent stirring. As the mushrooms and veggies finish cooking, remove them from the heat. Slice the mushrooms when they are cool enough to handle.
  7. As the veggies cool, brush both sides of the bread with oil and grill for a minute on each side—when it looks like light toast, it is done.
  8. Spread mayo on each slice of bread, and layer veggies in between to make a sandwich.

Grilled Veggie Sandwich with Pesto-Feta Mayo

Grilled Veggie Sandwich with Pesto-Feta Mayo

Grilled Veggie Sandwich with Pesto-Feta Mayo

Yield: 4 regular sandwiches or 2 double-decker sandwiches
Prep Time: 20 minutes
Cook Time: 15 minutes
Total Time: 35 minutes

This delicious grilled veggie sandwich features a flavorful pesto-feta mayo that you'll want to put on Everything. It's the perfect easy meatless meal!


For the Mayo:

  • 1/4 cup mayonnaise
  • Zest and juice of 1 lemon
  • 1/3 cup crumbled feta cheese
  • 2 tablespoons prepared basil pesto

For the Sandwich:

  • 1 small eggplant, cut into thin slices
  • Salt
  • 1 small zucchini, cut into thin slices
  • 1 small yellow squash, cut into thin slices
  • 1 large red bell pepper, cut into thin slices
  • 1 large red onion, cut into thin slices
  • 1/4 cup olive oil, divided
  • 1 tablespoon dried oregano
  • 2 portabella mushroom caps, stems removed
  • Black pepper, to taste
  • 8 slices bread (or 6 for two double-decker sandwiches)


  1. Whisk together all the mayo ingredients in a small bowl until well-combined. Refrigerate while you prepare the rest of the sandwich.
  2. Lay a dish towel down on a flat surface, then place the eggplant slices, in one layer, on top. Sprinkle liberally with salt. Let rest for 10-15 minutes. This pulls out any bitterness the eggplant might have. Place the eggplant in a colander, and rinse well with cool water.
  3. Preheat a grill to medium-high.
  4. In a large bowl, toss together the eggplant, zucchini, yellow squash, pepper and red onion. Drizzle with 2 tablespoons olive oil and the oregano. Toss to coat. Transfer to a grill basket.
  5. Brush both sides of the mushrooms caps with an additional tablespoon of olive oil. Season with salt and pepper.
  6. Place the grill basket and the mushroom caps on the preheated grill. Cook the mushrooms for 4-5 minutes, until they begin to release their moisture, then flip and cook an additional 3-4 minutes. Remove from the grill and slice thinly.
  7. Stir the veggies frequently and grill until they are tender, about 10 minutes. If you have any larger pieces, you may wish to remove them from the basket and cook them directly on the grill (I usually do this with eggplant). Once tender, remove from grill.
  8. Brush both sides of the bread with the remaining olive oil, grill each slice for a minute on each side until just toasted. Remove from grill.
  9. To assemble the sandwiches, spread the mayo on a slice of toasted bread. Layer with a single layer of each veggie. Spread mayo on another slice, and place on top.


This recipe will make four regular sandwiches or two double-decker sandwiches (if you want to unhinge your jaw!).

You'll need a grill basket to do this recipe. If you don't have one, I highly recommend heading to your local discount store and picking one up. All that seasonal stuff goes on clearance this time of year to make room for back to school stuff. Go get one!

Nutrition Information:
Yield: 4 Serving Size: 1 sandwich
Amount Per Serving: Calories: 532Total Fat: 32gSaturated Fat: 6gTrans Fat: 0gUnsaturated Fat: 24gCholesterol: 17mgSodium: 706mgCarbohydrates: 53gFiber: 7gSugar: 13gProtein: 12g

At Wholefully, we believe that good nutrition is about much more than just the numbers on the nutrition facts panel. Please use the above information as only a small part of what helps you decide what foods are nourishing for you.

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  1. Looking very delicious and mouth watering..I definitely gonna try this at my home,….thanx for sharing the recipe…..

  2. you are NOT alone. i could not keep mint (which i hear grows in adundance) and cacti alive 🙁

    i am not a vegetarian but i love grilled veggie sandwich over meat ones anyday.

  3. It’s my first year (actually first 8 weeks) with a space to grow veg and the only thing that’s growing that I had anything to do with is courgettes (which is also the answer to why we don’t have cute names for them!) so I have a feeling something like like to work off is going to come in handy. Although summer squash isn’t something I know, maybe I’ll look into for next year!