This is really a reminder to myself of the volume of onion mush that is produced from 1 kilo of sliced onions (it’s probably about a cup). I do know the onions reduce down, and I always think ‘I really should double this recipe’, but, you know, one of the last things you want to do when you’ve peeled and thinly sliced a kilo of onions, is to peel and thinly slice *another* kilo of onions! Still, when you put in effort to make onion mush, it would be nice to end up with more than a cup of delicious-ness (and it is delicious). Since peeling and slicing is the major hurdle in making mush, it would make sense to use a food processor, like Nigella suggests (the recipe is from How to Eat).
Recipe (more or less).
Peel one kilo of onions, and then slice very thinly. Add your fat (1 tbps of butter or LARD plus 3 tbps of olive oil, or 5 tbsp olive oil) to a heavy based pot over a low heat, and then add the onions once the butter/lard has melted, but has not started bubbling. Pack the onions down with a wooden spoon, sprinke with salt and then add 75 mL of Marsala (or cheap dry sherry in my case), topped up with 100 mL of boiling water. Take a piece of foil and pack it tightly over the onion, shiny side down, put the lid, and allow to simmer for 2 hours (check after 1 hour to ensure the onion is not browning or sticking to the pan). After 2 hours, take off the lid and foil, increase the heat and boil off the liquid. You will need to keep a fairly close eye on the mush at the point, and stir pretty constantly to make sure it doesn’t stick. A key point is that the onion does not turn brown until you start boiling off the liquid. I remember feeling quite worried the first time I made mush my onions were so pale at the end of the slow cook stage. However the sugar doesn’t caramelise until the water is gone – so don’t worry, your onions will go brown!
An exciting moment in making this batch of mush, was using my own LARD, when I rendered off a slow cooked pork shoulder a few days before. I just poured the fat off the slow cooker and cooled it in the fridge, ending up with a suprisingly pristine white fat that melts beautifully (and I feel good about not throwing it away. go LARD!). I do think you can cut down on the oil in the onions, though. I might ignore the addition of olive oil next time.
Anyway, the mush (or relish) is very delish and worked well on our umami burgers (which I essential followed this recipe, but replaced the applesauce with 1 tsp sugar and grilled in a frying pan). If only there was more…