Recipe: Red onion marmalade

I made this several months ago and intended to post about it when I knew it tasted OK (e.g. a month or so later).  I've just searched and it looks as if I didn't so, as I am making another batch as I type, filling the house with oniony pong despite the open windows and the fan, it's a good time to share it with you all.

This is the recipe, here, if you would like to see the original.

Ingredients:

1 good tbsp olive oil and a dollop of butter The original recipe says extra virgin but I don't see the point, given how long it has to be cooked and I added the butter because I wanted to.

1kg red onions (approx. 6), peeled, halved and sliced I didn't have enough so used some white onions and I sliced them by hand because that way you can get the thickness you want.

Sea salt and freshly ground black pepper

150ml red wine

3 tbsp balsamic vinegar

3 tbsp white wine vinegar

6 tbsp light soft brown sugar

Method:
Heat the oil and butter.  Add the onions with some ground black pepper and a good pinch of sea salt.  Stir well.

Cook over low to medium heat for about 30 minutes or longer until the onions soften and turn translucent, stirring occasionally so they don’t catch and burn. Slow cooking is essential at this point as this is where the delicious caramel taste is developed.

Increase the heat just a bit and add the wine and the vinegars.  Boil, reduce the heat and add the sugar, stirring well.

Cook on the low heat for around 30 to 40 mins until most of the liquid has evaporated.  Don't forget to stir occasionally to prevent sticking.

Clean and heat your jam jars.

Take the pan off the heat, taste and adjust the seasoning if necessary, although the flavours do mature with time and I found that it was just right last time.. Spoon into the warm, clean jars, cover with waxed paper discs,and screw on the lid (non metallic or coated with plastic), making sure there are no air gaps (I push the mixture down with a spoon to make sure), tighten the lids and label. Store in a cool, dark place for at least 1 month to allow the flavours to develop.  It keeps for around three months, the recipe says, although I had some after four months and it was gorgeous!