As much as I love juicy grilled beef burgers, my wife suggests my eating less red meat. The problem is solved as long as these delicious plant-based Portobello Mushroom “Burgers” are offered as a satisfying vegetarian alternative.


4 portobello mushrooms, 4-to-5-inches in diameter

3 tablespoons balsamic vinegar

2 tablespoons soy sauce

3 tablespoons olive oil

2 tablespoons Roman Holiday seasoning

4 ¼-inch-thick slices red onion

4 slices provolone cheese

4 ripe tomato slices

Baby arugula

Four favorite burger buns, toasted


  1. Remove the stems from the portobello mushrooms and place the caps in a shallow dish large enough to hold them in a single layer.
  2. In a small bowl, whisk together the balsamic vinegar, soy sauce, olive oil, and Roman Holiday seasoning. Pour this over the mushroom caps turning to coat evenly. Let marinate at room temperature for 20 minutes.
  3. Prepare a gas or charcoal grill for cooking over medium heat. When hot, brush the grates lightly with oil or spray with grilling spray.
  4. Place the mushrooms on the hot grill with the stemmed sides facing down. Place the red onion slices in the remaining mushroom marinade and toss to coat. Grill the mushrooms until lightly crusted brown, 3 to 4 minutes. Flip the mushrooms over and continue grilling for another 3 to 4 minutes. About a minute before the mushrooms are done cooking, top each with a slice of provolone cheese. Also add the onions slices to the grill. Close the grill lid for about 1 minute to melt the cheese.
  5. To serve, place a grilled portobello cap on the bottom of each toasted bun. Top with the grilled onions, tomato slices, and a handful of baby arugula. Add the top of the toasted bun, press lightly to sandwich together, and serve at once.

Serves 4


Written by Sarah Leah Chase

Sarah Leah Chase moved to Nantucket, Massachusetts, as a year-round resident in 1980 and opened a specialty food shop and catering business called Que Sera Sarah, which soon became an island institution.


Sarah develops recipes and concepts for her husband Nigel’s specialty food company, Coastal Goods. She lives with her family on Cape Cod, where she enjoys oystering and gardening as much as cooking.