Note: This jam will stay good in a sealed container in the fridge for up to 3 months. Red Onion Jam is a perfect accompaniment for a cheese plate or charcuterie, and goes particularly well with blue cheese.
- 6 cups finely diced red onions (about 4 large)
- 2 cups sugar
- 1 (750 ml) bottle dry red wine
- 1 cup red wine vinegar
Combine all ingredients in a large saucepan and bring to a simmer over high heat, stirring until sugar is dissolved. Reduce to a simmer and cook, stirring occasionally, until thick and syrupy and reduced to about 2 cups, 1 1/2 to 2 hours. Allow to cool, then transfer to an airtight container and store in the fridge.