Heat the butter and olive oil in a large frying pan on medium low heat until the butter has melted.
2 tbsp butter, 1 tbsp extra virgin olive oil
Twirl it around to mix the two fats.
Add the onions and mix well, coating the onions in the fat.
large white onions
Once the onions have heated through, after about a minute, turn the heat down to low.
Cook the onions for 20 minutes, stirring frequently, at which time, the onions will be a light golden colour.
Add a splash of liquid, stir well and continue cooking for another 20 minutes, at the end of which, the onions, will be soft, syrupy and a rich brown colour.
Water, Stock or Alcohol of your choice: cider, white wine
Add another splash of liquid, scraping the bottom and sides of the pan. This second deglazing will release all that sticky goodness to be absorbed back by the onions.
Cook for a final 5-10 minutes, turn the heat off and use as required.