Caramelized onions are a sweet and savoury wonderful addition to so many different recipes from flatbreads and grilled cheese sandwiches to savoury tarts and charcuterie plates. The trick is to…well, not burn them. Low & slow is the name of the game and with a little bit of attention, you can cook up a big batch to have on hand.

Before you start

Choose your onions. Any onion will do, so go ahead and experiment with flavours. Yellow onions are perhaps the most versatile.

A cast iron skillet is the perfect tool for the job. If you don’t have one (and you should), you can use a stainless steel pan. Non-stick surfaces aren’t great for good caramelization.

A metal spatula will make your life a lot easier.

How to Caramelize Onions

Makes approximately 2 cups of caramelized onions

Ingredients
5 large onions
3 tablespoons olive oil
5 teaspoons of butter
1 teaspoon of brown sugar
½ teaspoon of sea salt
1 tablespoon balsamic vinegar (optional)

Instructions

Halve & cut the onions into very thin slices.

Coat the bottom of a wide, heavy-bottomed sauté pan with the olive oil and butter and heat on medium heat.

Once the oil is hot, add the onion slices and stir. Make sure all of the onion is coated. Allow to cook slowly for 15 minutes, stirring occasionally to keep any bits from sticking to the pan.

After 15 minutes, sprinkle the onions with salt, sugar and balsamic vinegar (optional) and stir again to coat the onions. If the pan’s looking dry, add a little water or white wine—not much, just enough to get things juicy again.

Continue to cook the onions over low heat for another 10-15 minutes, stirring occasionally until sticky. You may need to add a little more oil here if it looks like the onions are burning.

Using a metal spatula, allow the onions to stick just enough to brown and then scrape up the browned bits and mix them back into the onions. Continue scraping and stirring until the onions are a deep brown colour. Remove from the pan and dig in! Caramelized onion keeps for several days refrigerated in an air-tight container.