- ¼ cup olive oil
- 3 large white or yellow onions, finely diced
- 2 sprigs rosemary
- 2 sprigs thyme
- 1 bay leaf
- ¾ cup granulated sugar
- ¾ cup white balsamic vinegar
- 1 teaspoon kosher salt, plus more to taste if needed
- In a large pot, heat olive oil over medium heat. Add the onions and cook, stirring occasionally until they become golden brown and begin to caramelize.
- Tie the rosemary, thyme, and bay leaf together with kitchen twine, then add into the pot with onions. Continue to cook, stirring occasionally until very fragrant, about 3-5 minutes.
- Turn heat to medium-low and sprinkle sugar over the onions. Let sugar melt, undisturbed, for 5 minutes. Then, turn the heat to medium-high and continue to cook the sugar undisturbed until it becomes a golden amber color, 5-6 minutes.
- Turn the heat back down to low and mix in the white balsamic vinegar. Cook until the mixture becomes thick and jammy, 7-10 minutes. Remove the herb bundle and season with salt adding more to taste if needed.
- Let the jam cool and then transfer to an airtight container. Onion jam can be stored refrigerated for up to 1 week.