This is one of my favourite condiments of all time.

I make two different versions of this jam, one for red onions and one for white onions, the only difference being the colour of the final product.  The recipe below is for the red variety.  To make the brown marmalade, at left, use white onions, dark brown sugar, and cider vinegar instead of red onions, white sugar, and red wine vinegar.

Red Onion Jam
adapted from River Cottage Preserves Handbook

Ingredients

• 120 g canola oil
• 1300 g red onion (about 4 large onions)
• 100 g granulated sugar
• 120 g crabapple jelly, or some other red fruit jelly, such as currant
• 200 mL red wine vinegar
• 1/2 tsp kosher salt
• 1/2 tsp fresh ground black pepper

Procedure

1. Heat the oil in a large pot over medium heat and add the onions.  Reduce heat to low, cover the pot and cook, stirring occasionally, until the onions are wilted and beginning to colour, about 40 minutes.
2. Add the sugar and jelly.  Increase the heat to medium and continue to cook, stirring more frequently, until the mixture turns dark brown and most of the moisture has been driven off, about 30 minutes.
3. Add the vinegar.  Increase the heat to high and cook rapidly until the mixture becomes gooey and a spoon drawn across the bottom of the pan leaves a clear track across the base, about 10 minutes.
4. Remove from heat and season with the salt and pepper.  Spoon into warm, sterilized jars and seal.  Use within a year.