On Labor Day I did what most Americans do—which is heat up the old grill and have a barbecue. So, what else is new? With me, it was that I didn’t go the usual burgers and franks route. I decided this time around to grill portobello burgers. That’s right, portobellos, as in mushrooms. In fact, you could call these mushroom steak burgers.  A while back it was discovered that portobello mushroom have a great texture, like steak or meat, except they’re richer in flavor. So why not portobello burgers? Portobello mushrooms are big and meaty, just like a regular hamburger or steak.  That makes them perfect for the recipe given. It’s  meaty mushrooms marinated in a mix of mustard, vinegar, olive oil and garlic. Then grilled and stuffed with a separate mix of roasted red peppers, black olives and scallions. Add some mayonnaise combined fresh rosemary and you have a dish worthy of the gods (or family and friends). Believe me, meat eaters will love this dish; and so will anyone who wants something new, different and delicious on the grill.



4 large portobello mushrooms, stems removed
1 large clove garlic, minced
1 tablespoon mustard (Dijon preferred)
2 tablespoons sherry vinegar
2 tablespoons olive oil, plus more for scallions and hamburger buns
Salt and ground black pepper to taste
½ cup mayonnaise
1 tablespoon minced fresh rosemary or 1 teaspoon dried
½ cup canned or jarred roasted red peppers
½ cup medium pitted black olives, chopped
6 large scallions, bottoms trimmed
4 hamburger buns
4 slices cheese (cheddar or provolone)


  1. Wash mushroom caps under cold running water and pat dry with paper towels.
  2.  Preheat grill to medium.
  3.  In a small bowl, combine the garlic, mustard, vinegar, olive oil, and a hefty pinch of salt and pepper. Brush this marinade on both sides of the mushrooms. Transfer to a zip-lock bag along with the remaining marinade. Marinate at room temperature for 20 minutes. Meanwhile, in a small bowl combine the mayonnaise and rosemary, then season with salt and pepper. In a medium bowl combine the peppers and olives, and season with salt and pepper. Set aside.
  4.  Drizzle the scallions with a little bit of olive oil and then grill, turning often until they re charred at the edges and crisp tender, about 3-4 minutes. Transfer them to a cutting board and let cool slightly. Chop the scallions and add them to the bowl with the peppers and olives.
  5.  Brush the hamburger buns with a little olive oil. Then grill until slightly toasted on both sides. Set aside.
  6.  Grill the mushrooms, gill side down, 3 to 4 minutes. Turn them over and grill on the second side until tender when pierced with a knife or fork, another 3-4 minutes. Spoon a quarter of the olive-pepper mixture evenly on top of each mushroom. Top with a slice of cheese, cover the grill and cook until the cheese melts, 1-2 minutes.
  7.  Spread the mayonnaise mixture on each hamburger bun. Top with mushrooms, and serve.
    Yield: 4 servings