Portobello mushrooms are a nutritious and satisfying alternative to burgers made with beef or turkey. Here they are accompanied by a spread of pureed cannellini beans for added protein -- and flavor. To clean the mushroom caps, wipe them with a damp paper towel; do not rinse or soak, or they will remain soggy even after cooking. This recipe is featured in the"Power Foods" cookbook.

The Martha Stewart Show, Episode 6074


Recipe Summary

Makes 4


Ingredient Checklist


Instructions Checklist
  • Heat a grill or grill pan to medium (if using a charcoal grill, coals are ready when you can hold your hand 5 inches above grill for just 6 to 8 seconds). In a food processor, puree one-quarter of the garlic (about 1/2 teaspoon), 1 tablespoon thyme, the cannellini beans, and 1 teaspoon oil until smooth. If mixture is too thick to spread, add a bit of water. Season with pepper, and pulse to combine.

  • Combine the remaining garlic and remaining 1 tablespoon thyme with 1 tablespoon plus 2 teaspoons oil in a shallow dish. Place the mushroom caps in the garlic mixture, and turn to coat. Season with pepper; drizzle with vinegar.

  • Place onion slices on a plate, and lightly coat each side with remaining 2 teaspoons oil. Grill the onions until lightly charred on the first side, about 3 minutes. Flip the onions, and continue grilling until tender and charred on the other side, about 3 minutes more. Transfer onions to a clean plate; cover to keep warm.

  • Working in batches if necessary, place mushrooms on the grill, stem side up. Grill until browned on the first side and juices have begun to collect in the centers, about 5 minutes. Flip mushrooms, and continue cooking until stem side of each cap is browned and center is tender, about 4 minutes more.

  • Split hamburger buns, and place cut side down on grill; cook just until warm and toasted. Spread 1/4 cup bean puree on the bottom half of each bun, and top with 2 grilled mushroom caps. Layer each with sliced cheese, grilled onions, and a small handful of arugula. Top with remaining roll halves, and serve.