Portobello Burger with Caramelized Red Onions

Portobello Burger with Caramelized Red Onions

serves 2 cooks in 10mins difficulty two

Mushrooms are often used in dishes that need a bit of “meatiness” added to them, so it’s no surprise that they work so well in this portobello burger which I love to serve with sweet caramelised onions, fresh lettuce, and tomato. The burger itself is crammed full of goodness – think chickpeas, broccoli, and spices to boost the flavour. Definitely give this a go for you next burger night and I reckon even the meat-eaters around the table will love them!

The Ingredients


1 Tbsp + 1 tsp melted coconut oil

1 cup Portobello mushrooms, gills removed and chopped

1 1/2 Tbsp flaxseed meal

1/4 cup + 1/2 Tbsp water

1 cup cooked white or garbanzo beans, rinsed and divided

1/2 cup minced broccoli, fresh only

2 Tbsp minced garlic

1/4 cup red onion, minced

1/2 tsp paprika

1/4 tsp salt

1/2 tsp black pepper

1/3 cup vegan parmesan cheese

1/4 cup plus 1 Tbsp panko or gluten-free panko


1 large red onions, thinly sliced

1/4 tsp salt

1/2 Tbsp coconut oil


2 buns of your choice

Optional: lettuce, tomato etc.


To make the onions, heat 1/2 Tbsp coconut oil over medium-low heat. Once hot, add onions and cook for 10 minutes, untouched. Add in 2 Tbsp water, stirring to combine. Let cook for 10 minutes without stirring. Continue this cycle of adding water and cooking for 10 minutes 2 more times until the onions are caramelized. Set aside.

In a small bowl, stir together flaxseed meal and water. Set in the refrigerator for 15 minutes, until thickened.

Heat 1 tsp coconut oil in a medium skillet over medium-high heat. Once hot, add mushrooms and cook for 5 to 7 minutes, until mushrooms are browned. Remove from heat and cool slightly.

Add beans and mushrooms to a food processor or blender and pulse until combined. It doesn’t have to be smooth, it can still be somewhat chunky.

Add the mushroom bean mixture to a large bowl. Stir in broccoli, garlic, onion, paprika, salt, and black pepper until everything is coated evenly.

Stir in flax seed mixture, cheese, and panko until combined. Set aside.

Add 1 Tbsp coconut oil to a medium nonstick skillet over medium heat. Once shimmering, use damp hands to scoop half of the mixture into your palm. Shape into a burger, pressing the mixture together well. If you are having trouble with the mixture holding its shape, add another Tablespoon of panko. Form the second patty.

Place patties in the oil, cooking for 3 to 5 minutes per side, until golden brown on both sides.

To assemble the burgers, add each patty to the bottom of a bun. Top with caramelized red onions, dividing evenly between the two burgers. Top with lettuce, tomato, and any other toppings you’d like. Serve immediately.

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