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.