The caramelized red onions are a true explosion of flavors that can enhance any dish with their sweetness and versatility: from fresh cheeses to aged ones, to burgers, to simple bread bruschetta. With this very easy recipe, you will be able to transform one of the simplest ingredients into a gourmet food, which can become the real star of your dishes, adding a touch of elegance and goodness to every meal.
To prepare the caramelized red onions, you will need few simple ingredients: red onions – if you find Tropea ones, they are the best for this recipe – a little butter, some sugar (just to enhance the natural sweetness of the onions), and a little vinegar. I used balsamic vinegar, but alternatively, you can use apple cider vinegar or red wine vinegar. The caramelization process, together with the use of vinegar, significantly reduces the pungent taste of the onions, making them pleasantly sweet and sour and easily pairable with a wide variety of flavors.
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- Difficulty: Easy
- Cost: Very cheap
- Preparation time: 5 Minutes
- Portions: 4 people
- Cooking methods: Stovetop
- Cuisine: Italian
- Seasonality: All seasons
- Energy 90.73 (Kcal)
- Carbohydrates 13.03 (g) of which sugars 8.64 (g)
- Proteins 0.99 (g)
- Fat 4.01 (g) of which saturated 2.59 (g)of which unsaturated 1.41 (g)
- Fibers 1.40 (g)
- Sodium 97.02 (mg)
Indicative values for a portion of 40 g processed in an automated way starting from the nutritional information available on the CREA* and FoodData Central** databases. It is not food and / or nutritional advice.
* CREATES Food and Nutrition Research Center: https://www.crea.gov.it/alimenti-e-nutrizione https://www.alimentinutrizione.it ** U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, 2019. https://fdc.nal.usda.gov
Ingredients for 1 small bowl (about 6 oz) of caramelized onions
- 12 oz red onions
- 1 tbsp sugar
- 1.5 tbsp butter
- 3.5 tbsp balsamic vinegar (about)
- 1 pinch salt
Tools
- 1 Cutting board
- 1 Knife
- 1 Pan non-stick with lid
How to Prepare Caramelized Red Onions
For the English version of this recipe click here!
To prepare caramelized red onions, start by peeling the onions, then slice them into not too thin slices (about 1/4 inch) (1). This way, even when cooking for a long time, they won’t fall apart but will maintain their consistency.
Gently separate the various onion rings obtained (2). In a thick-bottomed non-stick pan, melt the butter over low heat (3).
When it is completely melted, add the onions (4) and lightly salt them. Let them cook over low heat for a couple of minutes, stirring often.
Then add the sugar (5) and continue to cook for 7-8 minutes, stirring often, until the onions have softened slightly (6).
At this point, increase the heat and deglaze with the balsamic vinegar (7). A small note: I used 50 ml of a relatively “mild” balsamic vinegar, but if you use a very thick and aged one, a tablespoon or two will suffice, to be diluted in a little water if necessary, otherwise it will entirely cover the taste of the onions.
Let it evaporate for about a minute, until you no longer smell the strong vinegar odor. Cover with a lid and cook over low heat for about 5 minutes, until the onions are soft and perfectly caramelized (8).
At this point, remove the lid and, if necessary, cook for another minute or two without the lid, just long enough to evaporate any excess water (9).
Then transfer the caramelized red onions to a bowl or glass jar and let them cool completely. You can then serve them at room temperature.
How to Store Caramelized Onions
The onions prepared this way can be stored in the refrigerator for 3-4 days, closed in a glass jar.
FAQ (Frequently Asked Questions)
What goes well with caramelized onions?
The perfect pairing for caramelized onions is definitely with cheese, both fresh and aged: you can use them to accompany a nice cheese board, along with a small bowl of honey and one of jam.
Another common use for caramelized onions is to give an extra boost to a tasty sandwich with burgers, or with grilled eggplants and smoked cheese.

