- 1/4 cup extra-virgin olive oil
- 3 large sweet onions, cut into 1/4-inch dice
- 2 parsley sprigs
- 2 bay leaves
- 1 rosemary sprig
- 1 cup sugar
- 3/4 cup white balsamic vinegar
- In a large pot, heat the olive oil until shimmering. Add the onions and cook over moderately high heat, stirring occasionally, until golden brown, about 15 minutes.
- Tie the parsley, bay leaves and rosemary together with kitchen twine. Add the herb bundle to the diced onions and cook over low heat, stirring a few times, until fragrant, about 3 minutes. Sprinkle the sugar over the onions and cook, without stirring, until the sugar melts, about 5 minutes. Increase the heat to high and cook, without stirring, until an amber-brown caramel forms, about 6 minutes. Stir in the white balsamic vinegar and simmer over low heat, stirring a few times, until the jam is thick, about 5 minutes. Discard the herb bundle. Season the jam with salt and let cool to warm.
The caramelized onion jam can be refrigerated for up to 5 days. Serve warm or at room temperature.