I discovered onion jam at a cheese shop in Lyon where they sold it in small jars next to aged Comte. The woman behind the counter spread a spoonful on a slice of bread with a sliver of cheese and handed it to me. I bought two jars and started making my own when I ran out.
This recipe cooks 700 grams of chopped onions in browned butter with sugar, salt, and pepper, covered on low heat for thirty minutes. Then red wine and sherry vinegar go in, and you cook uncovered for another thirty minutes, stirring frequently, until it thickens into a dark, sticky jam. Into sterilised jars while still hot. A keeper for anyone who eats cheese.
Tips for Making Onion Jam
Brown the butter before adding the onions
Melt the butter over low heat until it turns brown and smells nutty. This is beurre noisette and it gives the jam a toasted, caramel-like base. 
Add the onions and sugar immediately after the butter browns. The sugar starts the caramelisation process from the beginning.
Cook low and slow
Thirty minutes covered, then thirty minutes uncovered. A full hour of cooking. Do not raise the heat to speed things up. High heat burns the sugars and makes the jam bitter.
Stir frequently during the uncovered phase. The wine and vinegar reduce and the jam becomes thick and sticky. It should coat the back of a spoon when done.
Onion Jam
- Total Time: 75 minutes
- Yield: Makes 1 jar 1x
- Diet: Gluten-Free, Omnivore
Description
Rich and savory-sweet onion jam, perfect for adding depth to pâtés or elevating simple sandwiches.
Ingredients
- 1 lbs (700 g) onions
- 1 oz (25 g) butter
- 5 oz (140 g) sugar
- 7 tablespoons sherry vinegar
- 1 cups (250 ml) red wine
Instructions
- Peel, slice, and roughly chop the onions into 2cm pieces.
- Melt the butter in a large saucepan over low heat until it turns brown.
- Add the onions and sugar, mix well, and season with salt and pepper.
- Cook, covered, over low heat for 30 minutes, stirring occasionally.
- Add the wine and sherry and cook for another 30 minutes without a lid, stirring frequently.
- Sterilize the jars in an oven at 356°F (180°C) for 10 minutes and fill while they are still hot.
Notes
- For deeper flavor, use a combination of yellow and red onions.
- If you don’t have sherry vinegar, substitute with red wine vinegar or balsamic vinegar.
- Store the jam in sterilized jars in the refrigerator for up to 2 weeks; it will keep for several months when canned properly.
- Prep Time: 15 minutes
- Cook Time: 60 minutes
- Category: Side Dish
- Method: Braising
- Cuisine: French-Inspired
Nutrition
- Serving Size: 2 tablespoons
- Calories: 100
- Sugar: 10
- Sodium: 100
- Fat: 5
- Saturated Fat: 3
- Unsaturated Fat: 2
- Carbohydrates: 15
- Fiber: 2
- Protein: 1
- Cholesterol: 5
Frequently Asked Questions
What kind of red wine should I use?
A wine you would drink. Avoid cooking wines with added salt. A medium-bodied red like a Merlot or Cotes du Rhone works well. The wine cooks down so the flavour concentrates.
How long does onion jam keep?
In sterilised jars in the fridge, up to two weeks. Properly canned in sterilised jars, several months. Sterilise the jars in the oven at 180°C (356°F) for ten minutes before filling.
What do you eat onion jam with?
Cheese, charcuterie, roasted meats, grilled burgers, or on toast. It works anywhere you want a sweet and savoury condiment. A spoonful stirred into gravy also works.
