By America’s Test Kitchen

When the king of mushrooms meets the heat of the grill, magic happens as its texture softens and its earthy, rich flavor deepens. Layer this portobello burger with melty goat cheese and peppery arugula, top it off with a tomato slice and smoky grilled onion, and you have a meatless burger featuring an irresistible combination of flavors and textures. Portobello mushroom gills can have an off-flavor, so we scraped them out to avoid a muddy taste. Before cooking, we lightly scored the smooth side of the mushroom with a crosshatch pattern to expedite the release of moisture and give the caps a more tender texture. 

Grilled Portobello Burgers with Goat Cheese and Arugula

4 portobello mushroom caps (4 to 5 inches in diameter), gills removed

1 large red onion, sliced into ½-inch-thick rounds (do not separate rings)

3 tablespoons plus 1 teaspoon extra-virgin olive oil, divided

2 garlic cloves, minced

2 teaspoons minced fresh thyme

¼ teaspoon table salt

¼ teaspoon pepper

2 ounces goat cheese, crumbled (½ cup)

1 cup baby arugula

¼ teaspoon balsamic vinegar

4 hamburger buns, toasted if desired

1 tomato, cored and sliced thin

1. Cut 1/16-inch-deep slits on top side of mushroom caps, spaced ½ inch apart, in crosshatch pattern. Brush onion with 1 tablespoon oil and season with salt and pepper to taste. Combine garlic, thyme, salt, pepper, and 2 tablespoons oil in bowl.

2A. For a charcoal grill: Open bottom vent completely. Light large chimney starter three-quarters filled with charcoal briquettes (4½ quarts). When top coals are partially covered with ash, pour evenly over grill. Set cooking grate in place, cover, and open lid vent completely. Heat grill until hot, about 5 minutes.

2B. For a gas grill: Turn all burners to high, cover, and heat grill until hot, about 15 minutes. Turn all burners to medium-high.

3. Clean and oil cooking grate. Place mushrooms, gill side down, and onion on grill. Cook mushrooms (covered if using gas) until lightly charred and beginning to soften on gill side, 4 to 6 minutes. Flip mushrooms, brush with oil-garlic mixture, and cook until tender and browned on second side, 4 to 6 minutes. Sprinkle with goat cheese and let cheese melt, about 2 minutes.

4. Meanwhile, cook onion, turning as needed, until lightly charred on both sides, 8 to 12 minutes. As they finish cooking, transfer mushrooms and onion to platter and tent with aluminum foil.

5. Toss arugula with vinegar and remaining 1 teaspoon oil in bowl and season with salt and pepper to taste. Separate onion rings. Place arugula and mushroom caps on buns. Top with tomato and onion. Serve.

Serves 4

Reprinted, with permission, from The Outdoor Cook (America’s Test Kitchen, 2023), americastestkitchen.com. 

The Outdoor Cook shows readers how to cook outside, whether they use a gas or charcoal grill, fire-top, flat-top grill, or smoker. It contains 150 recipes, which America’s Test Kitchen chefs have extensively tested.