The Portobello Burger

The Portobello Burger

Roasted tomato, fontina, and salad



Active Time:

~10 min

Total Time:

~22 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.


  • 2 portobello mushrooms
  • 1 red onion
  • 2 tablespoons sherry vinegar
  • 2 tablespoons Dijon mustard
  • 1 beefsteak tomato
  • 2 hamburger buns
  • 2 ½ oz organic cherry tomatoes
  • 2 oz spring lettuce mix
  • 2 tablespoons pumpkin seeds
  • 2 slices fontina

From Your Pantry

extra-virgin olive oil

cooking oil

kosher salt and black pepper


Brava metal tray

Brava glass tray

mixing bowls

Nutrition Information

730 calories per serving

Allergens: Milk, Wheat (Gluten)

Nutrition Facts


  • Chef's Picks
  • Two Tray Cooks
  • Lunch
  • Dinner
  • Vegetarian
  • Meal Kit
  • Bread
  • Californian
  • Glass Tray
  • Metal Tray
  • Recipes
  • Sandwiches
  • Serves 4
  • Vegetables
  • Weeknight

  1. step

    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.

  2. step

    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.

  3. step

    Slide glass tray into top shelf

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

  4. step

    Make salad

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

  5. step

    Warm buns

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

  6. step

    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 Brava.
    • 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.