This Mediterranean style Grilled Veggie Sandwich features eggplant, squash, red bell pepper and onions, slathered with pesto mayo and drizzled with balsamic vinegar. Focaccia or ciabatta bread elevates this flavorful and easy-to-make grilled vegetable sandwich. This recipe is vegetarian and easily vegan.

Table of Contents
Grilled Veggie Sandwiches for Summer or Fall!
It wouldn’t be summer or early fall with one of the most portable food groups around, sandwiches! This grilled veggie sandwich recipe hits all the marks. Here’s why you’ll love it:
- Enjoy Warm, Chilled or Reheated
- They’re Portable!
- Versatile – vegetarian or vegan friendly
- Make Ahead Ready
- Pesto Mayo (!!)
Best of all, this recipe is full of delicious seasonal veggies! And it’s simple to whip up.
Related: Check out my Sandwiches page for more delicious plant forward sammies!

Ingredients You’ll Need
- Bread – make with ciabatta, panino rolls, sliced focaccia (sourdough if possible). You just need a sturdy bread to stand up to all the veggies. No soft sandwich bread here.
- Olive Oil – (not extra virgin), sunflower or canola oil. Use a high smoke point oil otherwise the veggies can come out tasting bitter.
- Eggplant – look for smallish globe eggplant so that the slices are narrow enough to fit on the sandwich.
- Squash – enjoy with zucchini or yellow squash.
- Red Bell Peppers – you can roast these on the grill, then peel the skin, or you can use the convenience of prepared roasted red bell peppers.
- Red Onion – if needed you can soak in water for about 10 minutes to reduce their sharp flavor.
- Feta Cheese – I love the salty tang of feta on these grilled veggie sandwiches. You can use your favorite dairy free cheese here.
- Arugula – optional, but gives these veggie sandwiches a leafy green component and nice peppery flavor. Chopped spinach is really nice too!
- Balsamic Vinegar – just a splash over the veggies.
- Pesto Mayo – a mixture of mayo and pesto with gives the sandwich a fresh creamy component and a bit of garlic flavor. You can use prepared or homemade pesto. I like this Lemon Basil Pesto or Garlic Scape Pesto.


Quick Guide: How to Make Grilled Veggie Sandwiches
We’re firing up the grill for the tastiest sandwiches. You’ll start with a clean grill on medium heat. Oil the grates of the grill just before putting the veggies on by using a wadded up paper towel dipped in oil with tongs. Here’s how to make these grilled veggie sandwiches (see recipe card for details):
- First, grill your red bell pepper, turning to char on all sides.
- Second, slice the squash and eggplant lengthwise, 1/4 inch thick, then slice to fit the size of your bread. Lightly brush with vegetable oil.
- Third, grill the veggies. Meanwhile, peel the skin from the red bell peppers and slice.
- Next, whip up the pesto mayo.
- Last, slather bread of choice with pesto mayo, add the cheese and grill to warm the bread and melt the cheese.
Assemble the grilled vegetable sandwiches with the veggies and drizzle with a bit of balsamic vinegar (I like Ritrovo brand). Top with arugula and salt and pepper. Enjoy right away or save for later.


Expert Tips
- Make Ahead: this veg sandwich is delicious made ahead and enjoyed chilled or rewarmed. Simply wrap in foil and refrigerate within two hours or reheat it in a warm oven. For softer bread, warm it wrapped. You can also make everything in advance and assemble later.
- Enjoy with Hummus: instead of pesto mayo, enjoy this Mediterranean sandwich with a good slather of hummus. I like this Roasted Red Pepper Hummus.
- Make it Vegan: use vegan mayo, I like Vegenaise, enjoy with dairy free pesto and either omit the feta, or use dairy free feta.
More Fresh Veggie Sandwich Ideas
- Mushroom and Goat Cheese Veggie Panini
- Vegetarian Rueben Sandwich
- Greek Pita Sandwiches
- Italian Pressed Sandwich
- Chickpea Salad Sandwiches
- Pulled Portobello BBQ Sandwiches
Grilled Veggie Sandwich Recipe
Ingredients
- 2, 14 ounces (420 grams) Red Bell Peppers medium* (see note)
- 1, 10 ounce (275 grams) Zucchini medium-large
- 1, 12 ounce (340 grams) Globe Eggplant slender or two smallish eggplants
- 1/3 cup (70 grams) Olive Oil
- 3/4 cup (172 grams) Mayonnaise
- 3/4 cup (150 grams) Pesto I like lemon basil
- 1 Loaf of Focaccia or Ciabatta Rolls enough for 4 sandwiches (about 4 inches ea)
- 1/2 cup (85 grams) Feta Cheese crumbled, I like sheep's milk feta
- 1/2 Red Onion sliced thin
- Salt, Pepper, Red Pepper Flakes
- Balsamic Vinegar a few splashes or drizzle per sandwich
- 4 Hand Fulls of Arugula or chopped spinach
Instructions
Prep the Grill
- Heat gas grill on medium high heat. Once hot oil the grates by using a wadded up paper towel dipped in oil with tongs.
For the Grill
- For the Peppers: Place the peppers directly on the grill grate, using tongs to rotate the peppers as they char, getting each side, top and bottom blackened. This takes about 12-20 minutes. Remove the pepper from the grill, placing the pepper in a bowl. Cover for 10 minutes to steam (this will help the skin slip off with ease). Under running water, when the pepper is cool enough to handle, slip off the skin, remove the stem and seeds. Pat the pepper as dry as possible using paper towel. Slice into wide strips. Set aside
- For the Zucchini & Eggplant: Slice the zucchini and eggplant lengthwise into 1/4 inch thick strips (you'll want to go thicker than thinner). Cut in half crosswise to fit the size of the bread. Using a pastry brush, lightly brush both sides with oil. Using tongs, transfer the slices onto the grill, turn heat down to medium heat and sprinkle with salt, pepper and red pepper flakes. Grill each side for about 5-6 minutes, flipping carefully so they don't fall through the grates. They should be tender and charred when ready. Remove from grill and set aside.
For the Pesto Mayo
- In a medium bowl, mix the mayo and pesto. Set aside.
Assemble the Veggie Sandwiches
- Slice the bread and slather both sides with pesto mayo. Sprinkle one side with feta. Place bread on the grill, cheese and pesto mayo sides up – I use the warming rack – close lid and allow the cheese to soften and the bread warm, for about five minutes.
- Transfer bread to a cutting board and layer the ingredients: eggplant, zucchini, roasted red pepper, and onions. Drizzle with balsamic vinegar, sprinkle with salt and black cracked pepper. Top with arugula and either share open faced or top with remaining slice of bread. Slice in half if desired. Share warm, room temperature or chilled. They can be held at room temperature for about two hours, afterwards you'll need to refrigerate them.
To Store
- The ingredients can be made ahead and stored in the fridge up to three days in advance for an assemble later kind of sammie. Or store assembled sandwiches wrapped in foil. They can be enjoyed chilled or warmed. Warm in a 350 Fahrenheit (180 Celsius) oven for about 15-20 minutes unwrapped for crisper bread, wrapped for softer bread. The sandwiches tend to get soggy the longer they set in the fridge, so enjoy them within a day or two. Rewarming unwrapped takes the soggy off.
I love grilled veggies during the summer Traci! And this sammie has all my favorites! And I love the pesto mayo too!
We are on the same page, Mare! That pesto mayo really makes the sandwich!