The Portobello Burger narrow display The Portobello Burger wide display

The Portobello Burger

Roasted tomato, fontina, and salad


Active Time:
~10 min
Total Time:
~20 min

About this Recipe

For this veggie burger, Chef Travis wanted to use a whole ingredient instead of a processed patty. Portobellos are packed with concentrated mushroom flavor, and the roasted tomato adds even more umami that will leave you ready for more.



Prep portobellos & onion

  • Remove stems from portobellos and scrape out gills with a spoon. Wipe away any soil from mushroom caps with a damp paper towel.
  • Place mushrooms, stemmed side up, in Zones 2 and 3 of Brava glass tray.
  • Peel red onion and cut two ¼-inch-thick slices.
  • Place onion slices in Zone 1 of Brava glass tray.
  • Finely dice 1 tablespoon of remaining onion and set aside for vinaigrette. You will have some onion left over.


Prep vinaigrette & tomato

  • In small bowl, combine sherry vinegar, ½ teaspoon Dijon mustard, diced onion, ¼ cup extra-virgin olive oil and a pinch of salt and pepper; stir well. Save remaining mustard for serving.
  • Pour 1½ teaspoons vinaigrette into each mushroom cavity. Save remaining vinaigrette for salad.
  • Season mushrooms with a pinch of salt.
  • Cut two ½-inch-thick slices of beefsteak tomato. You will have some tomato left over.
  • Place tomato slices in Zone 1 of glass tray next to onion.
  • Drizzle tomato and onion slices with 1 teaspoon cooking oil and season with a pinch of salt.


Slide glass tray into top oven shelf

  • Select “Portobello Burger” on your oven touchscreen and follow instructions.
  • While food cooks, arrange buns, cut side up, on Brava metal tray.
  • Next, prepare salad.


Make salad

  • Cut cherry tomatoes in half.
  • In large bowl, toss together spring lettuce mix, cherry tomatoes and pumpkin seeds.


Warm buns

  • When your food is done, remove glass tray from oven, immediately slide metal tray into top oven shelf and close door. The residual heat will warm buns.


Assemble burgers, dress salad & serve

  • Place a slice of roasted tomato and onion inside each mushroom cavity, then top with a slice of fontina.
  • When fontina has melted (about 1 minute), remove buns from oven.
  • If desired, spread remaining Dijon mustard on buns.
  • Place a mushroom on each bottom bun and cover with top buns.
  • Season salad with a pinch of salt and pepper, then toss with remaining vinaigrette to taste. You may have some vinaigrette left over.
  • Divide salad between individual plates and add burgers.