Onion Jam

Sweet, jammy and tangy with a concentrated onion flavour, this onion jam recipe is to die for.

5 from 1 vote

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Prep Time 15

Cook Time 30

Ingredients

250g yellow onions
2 garlic cloves (original recipe was 1)
1 tbsp olive oil
35g butter
35g brown sugar
pinch of dried oregano or thyme
1 cinnamon stick
60ml sherry vinegar (See Recipe Note 1)
Salt and pepper to taste

Instructions

Slice up onions.
Chop up garlic
Melt butter in a heavy-bottomed pan over high heat.
Add onions and garlic, and stir well to coat with butter. Then add sugar, oregano, cinnamon and some salt and pepper.
Reduce heat and cook uncovered for 10 minutes.
When onions are soft enough to break when pressed against the side of the pan with a spatula, pour in the sherry vinegar.
Simmer everything, uncovered, over high heat, to reduce the liquid. You must stir frequently to avoid burning. This process may take about 10-15 minutes.
Once the onions are a deep brown colour and sticky and syrupy, draw a spoon across the bottom of the pan. If this clears a path that fills rapidly with syrupy juice, your onion jam is ready.
Leave to cool in the pan, then scoop into sterilised jars and seal. This can be eaten straight away or kept in the refrigerator for up to 3 months.

Notes

Onion Jam - Quick FAQ

1. What is the difference between onion jam and fried onions?

Onion jam is a sweet-sticky condiment achieved through a slow-cooking process involving two key scientific reactions: the Maillard reaction (browning) and caramelization (the breakdown of sugars). Unlike basic fried onions, onion jam has a complex, concentrated flavor and a meltingly sweet, jam-like texture.

2. How long does it take to make homemade onion jam?

The cooking time for onion jam depends on the volume of onions used. While a large batch (1kg) can take up to 2 hours of constant stirring to achieve full "jamminess," smaller batches (around 250g) can be caramelized in approximately 30 to 45 minutes.

3. What are the best onions to use for onion jam?

Large yellow or red onions are the best choice for onion jam because they are sweeter and milder than smaller varieties. You should avoid using shallots (small onions), as they do not provide the same mellow sweetness required for the jam.

4. What gives onion jam its dark, sweet flavor?

The deep, molasses-like sweetness in onion jam comes from the caramelization of the onions' natural sugars, supplemented by the addition of brown sugar or molasses. These ingredients help the onions break down into a dark, jammy consistency.

5. Why do you add vinegar to onion jam?

Vinegar, such as Sherry vinegar, is added to onion jam to provide a gentle tartness. This acidic component is essential to balance the heavy sweetness and savory notes of the caramelized onions, creating a more sophisticated flavor profile.

6. Can I use white sugar instead of brown sugar for onion jam?

Yes, you can use white sugar, but brown sugar or molasses is recommended for the best results. Brown sugar contains molasses, which contributes to a darker color and a deeper, more complex sweetness that white sugar lacks.

7. What herbs go best with onion jam?

Thyme is the traditional herb used in onion jam recipes, but it can be easily substituted with oregano or general Italian herbs. These savory herbs complement the sweetness of the onions without overpowering the condiment.

8. Do I need to stir onion jam constantly while cooking?

Yes, making onion jam requires active cooking. To prevent burning and ensure even caramelization, you must stand over the stove and stir the onions regularly for the duration of the cooking process until the desired texture is reached.

9. How long can I store homemade onion jam?

When properly stored in a sealed jar and kept in the refrigerator, homemade onion jam will stay fresh and flavorful for up to one month.

10. What can I serve with onion jam?

Onion jam is a versatile "mother of all condiments." It is traditionally served with Western-style burgers, but it is also spectacular when spread on plain buttered sourdough bread or used to add a savory-sweet depth to cheese boards.