Sweet Onion Jam
Ingredients
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- 3 pounds sweet onions – halved and thinly sliced (~7.5 medium sweet onions)
- 2 tbsp extra-virgin olive oil
- 2 tbsp unsalted butter
- 1 1/4 tsp kosher salt
- 1/2 cup light brown sugar
- 1/2 cup balsamic vinegar
- 1/4 cup water
- 1/2 tsp black pepper – freshly ground
- 2 tsp fresh thyme leaves
- 1 bay leaf
Instructions
1. Trim, halve, and thinly slice the sweet onions.
2. Heat the olive oil and butter in a wide, heavy pot over medium heat until the butter foams, about 1 minute.
3. Add the onions and kosher salt; cook, stirring occasionally, until wilted and translucent, 10–15 minutes.
4. Reduce heat to medium-low and continue cooking, stirring and scraping the pot occasionally, until the onions are deep golden brown and reduced, 30–40 minutes; adjust heat as needed to prevent scorching.
5. Stir in the brown sugar and black pepper until the sugar dissolves, about 1 minute. Add the balsamic vinegar, water, thyme leaves, and bay leaf; simmer uncovered, stirring occasionally, until thick, glossy, and jammy, 10–15 minutes. The mixture should hold a clean trail when a spatula is drawn through it.
6. Remove and discard the bay leaf. Taste and adjust salt. Cool to room temperature, then transfer to a clean jar and refrigerate. Serve chilled or at room temperature.
Sweet Onion Jam is a slow-cooked condiment that concentrates the natural sugars of sweet onions into a glossy, spoonable spread. The flavor is a balanced play of deep caramel sweetness, gentle acidity, and savory aromatics, with a texture that is soft, silky, and jam-like. It pairs beautifully with cheeses and charcuterie, enriches burgers and sandwiches, and brings a mellow sweetness to roasted meats and vegetables.
While onion preserves appear in many European traditions—French confit d’oignons and British onion marmalade among them—the use of distinctly sweet onions like Vidalia, Walla Walla, and Maui popularized this style in American kitchens. As balsamic vinegar became widely available in the late 20th century, it joined cider vinegar and wines as common acidifiers, lending color and complexity. Today, sweet onion jam sits comfortably at the intersection of pantry staple and entertaining essential, bridging old-world techniques with modern American ingredients.