---
title: Mega Mushroom Burgers
source:
  name: HelloFresh
  url: "https://www.hellofresh.com/recipes/w22-r9-58f0cf5951d3f11a4d4888f2"
servings: 4
prep time: 10 minutes
cook time: 20 minutes
time required: 30 minutes
difficulty: Easy
allergens: [Eggs, Wheat, Soy]
tags: [Spicy, Vegetarian, Burgers, Quick, American]
rating: 4.0
rating_count: 845
source_chef: Recipe Development Team
review_highlights:
  - theme: Flavor
    text: Tangy balsamic glaze and meaty portobellos make a satisfying burger
image: "https://images.recipes.furrysalamander.com/mega-mushroom-burgers.avif"
---
Wash and dry all produce. Peel @yellow onion{1%unit}, then thinly slice crosswise and separate into rings. Slice @roma tomato{1%unit} into thin rounds. In a #small bowl{}, combine @mayonnaise{3%tbsp} and @hot sauce{2%tsp} to taste. Set aside.

Heat a drizzle of @olive oil{3%tbsp} in a #large pan{} over medium heat. Add onion and cook, tossing, until softened and browned ~{4%minutes}. Season with salt and pepper. Remove from pan and set aside.

Rub @portobello mushrooms{4%pieces} all over with a large drizzle of olive oil. Season with salt and pepper. Add to same pan over medium heat. Cook until just tender ~{4%minutes} per side. Pour 1½ tbsp @balsamic vinegar{3%tbsp} into pan and cook until reduced by half ~{1%minute}. Toss to coat mushrooms, then remove from pan and set aside.

Wash and dry same pan, then return to stove over medium heat. Split @potato bun{4%pieces} in half down center. Add to pan cut side down. Toast until golden brown ~{3%minutes}.

Halve, pit, and scoop flesh from @avocado{1%unit}, then roughly chop. Place in a #small bowl{}, then mash with a fork until mostly smooth. Season with salt and pepper.

In a #medium bowl{}, toss @arugula{2%oz}, a drizzle of olive oil, remaining balsamic vinegar, and a pinch of salt and pepper. Spread spicy mayo on buns, then add a mushroom to each bun. Top with tomato, onion, and avocado. Serve with salad to the side.