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portobello mushroom burger ready to eat

Portobello Mushroom Burger – 5:2 Diet Plus

An easy and low calorie alternative for vegetarians which can be cooked on the BBQ or under the grill.  Portobello Mushroom Burgers are a delicious alternative to their meaty cousins

Course Lunch, Main Course
Prep Time 10 minutes
Cook Time 15 minutes
Total Time 25 minutes
Servings 1


  • 1 Large Portobello Mushroom
  • 1 Thin slice Leerdamer light cheese Or similar
  • 2 teaspoons Balsamic vinegar
  • 2 teaspoons Olive oil
  • 1/2 teaspoon Rose Harrissa
  • 1/2 Medium Red Onion finely sliced
  • 1 teaspoon Olive oil
  • 1 Thin slice Tomato
  • 1 teaspoon Low-calorie Mayo
  • 1 Handful Salad Greens
  • 1 Burger Bun


  1. Mix the balsamic, 2 teaspoons of oil and rose harissa. Use to baste the mushroom and put to one side for 20 minutes or so
  2. Gently fry the red onion in a teaspoon of olive oil till caramelised. Put to one side and keep warm

  3. Grill the mushroom on a griddle or barbecue, top side up for 2-3 minutes, then turn. Baste well with whatever is left of the marinade
  4. Continue to grill, topping the mushroom with the cheese slice for the last 2 minutes. Put to one side and keep warm.

  5. Split the burger bun, grill the inside till toasted.

  6. Put your burger stack together. Top the base of the roll with the mushroom (cheese up), then add a good spoon of caramelised onion, then add tomato, then salad greens. If liked, add mustard, ketchup, mayo or a mixture of all three.

  7. Enjoy!