Slow Cooker Caramelized Onions Recipe | Vegan in the Freezer (2024)

FAQs

Can you caramelize onions and freeze them? ›

Caramelized Onions Recipe Tips

Stored in an airtight container in the fridge, they'll keep for a week. You can also freeze them for up to two months. I like to freeze caramelized onions in ice cube trays. That way, I can easily thaw enough for a single dish and save the rest for another use.

Let your slow cooker do all the work of making beautifully caramelized onions. Freeze what you don't use right away so you'll have caramelized onions ready in a snap for soups, burgers, omelets, pizzas, and more.

It can be nice to cook the onions beforehand, as the flavour is different to when you put them in raw, but experiment both ways as you may find you prefer one. It can also be good to brown meat to give it some colour, but again, this is not essential.

Refrigerate caramelized onions in a tightly covered container for up to 1 week. Freeze caramelized onions in a freezer safe zip top bag or a freezer safe container for up to 3 months.

Let the cooked onions thaw in the refrigerator overnight before adding to soups, pastas and braises, or using as a burger topping.

The Best Way to Freeze Onions

Standard freezer bags are likely not thick enough, so double or triple-bag them. The onion's odor can permeate a freezer and it will go through thin bags.

Since you can just as easily caramelize one onion as five or six of them, I make a big batch of caramelized onions at once, and then freeze what we won't use within a few days to have on hand for quick meals.

Place them in an airtight container, freezer bag, or wrap them tightly in aluminum foil or plastic wrap. Raw onions will last up to eight months in the freezer. Cooked onions can be frozen for up to 12 months when stored in an airtight container or freezer bag.

How Long It Takes to Caramelize Onions in a Slow Cooker. It's almost impossible to overcook these onions, but I've found that 10 hours makes soft, lightly browned onions that still have a bit of bite.

What cannot be cooked in a slow cooker? ›

If you cook red onion with alkaline foods, such as nuts, lentils, and some vegetables, those anthocyanins revert to their blue hue. The same is true of red cabbage. To maintain the red hue, add a little acid, such as a splash of vinegar or a squeeze of lemon juice.

You can use just oil, or a combination of butter and oil—the choice is yours! If you pack too many onions into your pan, they'll steam and produce water. Eventually, they will caramelize—but it will take much longer to get them there.

You can use either oil or butter to caramelize onions — but ideally, you use a combination of both! I like to use olive oil, and this cooking fat tolerates heat particularly well. Meanwhile, butter adds a distinctly rich flavor to the caramelized onions.

Our Test Kitchen likes to use butter when caramelizing onions, as it offers the richest flavor. If you avoid dairy or don't have butter, you can caramelize onions in other fat such as margarine or olive oil. Add the onion slices. It's okay if they overlap a bit here because they'll shrink as they cook down.

Yup, those flavor-packed little strands of sweet cooked onions freeze beautifully, so why not make a bigger batch the next time you're caramelizing some for a recipe, or find yourself with a big bag of onions to use up.

The thing about cooking so many onions, though, is that you probably won't need that many at one time. So there's an essential second move whenever you're making caramelized onions: Freeze them. Stashed in an ice cube tray, caramelized onions will keep indefinitely in the freezer.

Caramelized onions will keep for up to 5 days in an airtight container in the fridge. The fat will separate from the onions, but a quick reheat in the microwave or on low on the stove combined with a bit of stirring will revive the texture.

The best way to reheat caramelized onions is to utilize that fat and reheat them in a pot over low heat. You shouldn't need to add any extra oil or butter and should only take about five minutes. If you're in a pinch, you can microwave them, but the microwave does have the potential to unevenly overcook them.