Caramelised onions become tastier and richer when a simple ingredient is added at the end of cooking, according to Chef Lindsey Farr. Butter is essential for cooking caramelised onions, as it “adds richness and flavour” and is “where a lot of the depth comes from”.
Finish with a knob of butter
Lindsey urged: “Finish with an extra knob of butter right before serving for a silkier texture.” Because butter contains milk solids, it kicks off the browning process more quickly than vegetable oils do, and it glazes the onions more beautifully. It is also more flavourful than most neutral oils like vegetable, olive, rapeseed, and sunflower oil.
Best onion varieties to use
Red onions, yellow onions, white onions, shallots, and extra-sweet varieties are all great for caramelising – each yields slightly different results, some sweeter, some more bitter. Often, you get the best results by using a mixture of different onion varieties, though this is by no means a requirement.
Red onions have a deeper flavour, with a slightly bitter edge and less sweetness. Yellow onions have lots of bright flavour, very mild bitterness, and a sweetness backing it up. Shallots have a really good balance of sweetness, with both bright flavours and deep, rich ones, and just a hint of bitterness.
How to make caramelised onions tastier
Ingredients: one quarter cup of unsalted butter, one tablespoon of olive oil, 900g of onions (cut in half lengthwise and sliced a quarter-inch thick), one teaspoon of sugar, sea salt to taste, and black pepper to taste.
Method: start by melting the butter and olive oil in a large pan over medium-high heat, which should take about one to two minutes and look glossy and smooth. Add onions and stir to coat evenly, then spread them out into an even layer so they cook consistently. Sprinkle with sugar to help start the caramelisation process early. Cook, stirring occasionally, until softened, about 15 minutes. Maintaining medium heat at the start helps prevent burning.
Continue cooking, stirring every few minutes, until deep golden brown and jammy, about 30 to 45 minutes more. Lindsey pointed out that the biggest mistake people make when learning how to caramelise onions is rushing the process. If they start to brown too quickly, lower the heat. True caramelisation is slow and controlled, not aggressive. It typically takes 45 to 60 minutes to “properly caramelise onions”. Faster methods often result in uneven browning or burning.
Remove from heat and season with salt and pepper. Stir well and use immediately or store.
