Vegetarian Portobello Mushroom and Avocado Burger

Vegetarian Portobello Mushroom and Avocado Burger

The Spruce / Diana Chistruga

Prep: 10 mins
Cook: 20 mins
Total: 30 mins
Servings: 4 servings
Nutrition Facts (per serving)
443 Calories
27g Fat
44g Carbs
10g Protein
Show Full Nutrition Label Hide Full Nutrition Label
Nutrition Facts
Servings: 4
Amount per serving
Calories 443
% Daily Value*
Total Fat 27g 35%
Saturated Fat 4g 21%
Cholesterol 0mg 0%
Sodium 701mg 30%
Total Carbohydrate 44g 16%
Dietary Fiber 9g 34%
Total Sugars 8g
Protein 10g
Vitamin C 12mg 61%
Calcium 130mg 10%
Iron 3mg 16%
Potassium 837mg 18%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

Portobello mushrooms make for a great veggie burger option for a vegetarian barbecue or vegan cookout. This recipe tops pan-fried or grilled portobello mushrooms with a perfectly cool (but quick to whip up) avocado and yogurt sauce.

For a vegan and non-dairy portobello mushroom burger, omit the yogurt sauce or make it with non-dairy soy or coconut milk yogurt.

Avocados from Mexico provided this recipe, which is perfect for a hot summer evening. You can include your favorite condiments or additions such as lettuce, fresh spinach leaves, or sliced tomatoes. Stack it up or keep it simple.


  • 4 medium portobello mushrooms, stems removed

  • 1 medium onion, cut into 1/2-inch slices

  • 3 tablespoons olive oil

  • 3/4 teaspoon salt, divided

  • 1/2 teaspoon freshly ground black pepper, divided

  • 1 avocado, peeled and sliced

  • 2 tablespoons low-fat yogurt

  • 1/2 teaspoon garlic, minced

  • 4 hamburger buns, lightly toasted

  • 4 jarred roasted red peppers, optional

  • Lettuce, optional

  • Tomato slices, optional

Steps to Make It

  1. Gather the ingredients.

    Vegetarian Portobello Mushroom and Avocado Burger ingredients

    The Spruce / Diana Chistruga

  2. Lightly brush the individual mushrooms and onion slices with a bit of olive oil on both sides. Sprinkle the mushroom and onion slices with 1/2 teaspoon of the salt and 1/4 teaspoon of the pepper; reserve the remaining salt and pepper.

    mushrooms on a plate and onions in a bowl

    The Spruce / Diana Chistruga

  3. Heat large a skillet or grill pan over medium heat until hot. Add the lightly oiled portobello mushrooms and allow them to cook until fully tender, 8 to 10 minutes, turning once.

    mushrooms cooking in a skillet

    The Spruce / Diana Chistruga

  4. Once the portobello mushrooms are fully cooked, transfer them to a plate, cavity-side up, and cover the mushrooms lightly with a paper towel or a kitchen cloth to keep them warm.

    paper towel on top of mushrooms

    The Spruce / Diana Chistruga

  5. In the same skillet or grill pan, cook the onion slices until lightly golden brown on both sides, about 8 minutes, turning occasionally.

    onions cooking in a skillet

    The Spruce / Diana Chistruga

  6. While the onions are cooking, start to prepare the avocado and yogurt sauce. In a small bowl, combine half of the avocado, yogurt, minced garlic, and the remaining 1/4 teaspoon of salt and black pepper. Using a fork, mash everything together until smooth and creamy.

    in a small bowl, combine half of the avocado, yogurt, minced garlic, salt and pepper

    The Spruce / Diana Chistruga

  7. To serve and assemble your portobello burgers, spoon the onions and the optional roasted red peppers into the grilled mushroom cavities, divided equally.

    spoon the onions and roasted red peppers into the grilled mushroom cavities

    The Spruce / Diana Chistruga

  8. Spread the smooth avocado mixture on the bottom of each bun and then top each with the stuffed mushrooms. Top each burger with the remaining sliced avocado and any additional veggie burger fixings you'd like.

    Vegetarian Portobello Mushroom and Avocado Burger on a plate

    The Spruce / Diana Chistruga


  • If you have any leftovers, refrigerate them and use them within three days. You can also grill the mushrooms ahead of time, refrigerate them, and heat them up for serving later.
  • To reheat, either microwave them for 1 minute, grill them briefly, or cook in a frying pan with a bit of oil.