Portobello and Pineapple Teriyaki Veggie Burgers

Using a small spoon, delicately scoop out and discard the dark brown gills from the underside of each mushroom.

Wipe mushrooms gently with a moist paper towel to remove any remaining debris then transfer to a wide, shallow baking dish along with the pineapple rings.

Put 3/4 cup of the reserved pineapple juice (save remaining for another use), soy sauce, sugar, garlic, ginger and sesame oil into a small bowl and whisk together to make a marinade.

Pour marinade over mushrooms and pineapple, cover and set aside, turning occasionally, for 1 to 2 hours.

Prepare a grill for medium-high heat cooking.

Meanwhile, remove mushrooms and pineapple from marinade and set aside.

Transfer marinade to a small saucepan; bring to a boil over medium-high heat.

In a small bowl, stir together 1/4 cup water and cornstarch then whisk into marinade and boil until thickened, about 1 minute more; set aside.

Working in batches, grill mushrooms and pineapple, gently flipping once, until hot throughout and tender, 3 to 5 minutes.

Transfer to buns, top with lettuce and serve with teriyaki sauce on the side, if you like.