Caramelized onions for burgers and onion soup

Scorrere verso il basso

Have you ever wondered how to prepare those beautiful, sweet and delicious caramelized onions for burgers (classic or vegetarian) or for French onion soup? This is a recipe for perfect caramelized onions that I’ve been using for many years, tried and infallible. They are perfect as a condiment or a side dish for many dishes such as meat, fish, gratin, frittata, soups and even pasta and ravioli. If you are looking for a perfect recipe where you can use these onions, check my Chickpea and zucchini veggie burger, otherwise go ahead and find out how to prepare them.

Caramelized onions for burgers and onion soup

Sweet, golden and soft caramelized onions that are perfect for seasoning burgers, fish, meat, French onion soup and more.
5 from 1 vote
Prep Time 3 minutes
Cook Time 40 minutes
Total Time 43 minutes
Course Side Dish
Cuisine gluten free, vegetarian
Servings 1 generous cup
Calories 654 kcal


  • 800 g white onions
  • 1 tablespoon butter I used unsalted butter made by Lurpak
  • vegetable stock or water optional


Instructions caramelized onions for burgers and onion soup

  • Peel the onions and cut them in half. Remove the root and slice in half-moon shape. Melt a tablespoon of butter in a large pan. Lower the heat and add the first half of the onions.
  • The trick here is not to fill the pan immediately with all the onions. If there is not enough space they do not have the surface large enough to release moisture and cook evenly. Cook for a few minutes, stirring occasionally, then add the rest of the sliced onions and stir.
  • The next step is very simple you have to cook your onions at a very low flame stiring them rarely for 15 minutes. Do not stir them too much or they will start to release the moisture too quickly and may burn. Instead we need them to get soft and to caramelize. After the first 15 – 20 minutes my onions look like this.
  • Continue cooking for another 15 – 20 minutes to obtain the perfect browning for the French onion soup.
  • Continue cooking if you want your onions even more gold or amber. You can add a couple of tablespoons of vegetable stock or water to deglaze the pan and extend the caramelization time.


The nutritional values are generated automatically for indicative purposes only and are therefore not completely accurate.


Serving: 1cupCalories: 654kcal
Keyword barbecue recipe, basic recipe, burger, easy side dish, onions, vegetarian side dish
Tried this recipe?Let us know how it was!

You can store them in the fridge for up to a week.

lot of love. B.

p.s. If you are looking for an amazing recipe with red onions check my Perfect Italian red onion marmalade.

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