Slow Cooker Caramelized Onions:
Sweet, Dark & Memorable!

So memorable, these onions, just thin slices of onion cooked until soft and dark and sweet in the slow cooker. My recipe for Caramelized Onions is "extra special" thanks to tiny touches of brown sugar and dry sherry. And now? My recipe is "extra easy" by switching from cooking the onions on the stove to cooking them either in a slow cooker or "slow cooking in the oven".

Real Food. Vegetarian, Easily Switched to Vegan. Low Cal. Low Carb. Weight Watchers Friendly. Gluten Free. Great for Meal Prep.
Slow Cooker Caramelized Onions, another building block for the inspired kitchen ♥ Weight Watchers Friendly. Gluten Free. Easily Vegan. Great for Meal Prep.

"Do You Still Make Your Three-Hour Onions?"

Sliced onions for Slow Cooker Caramelized Onions, another building block for the inspired kitchen ♥ Weight Watchers Friendly. Gluten Free. Easily Vegan. Great for Meal Prep.

The question startled me. It came from my cousin's wife Sue during a visit this summer.

Wow, mighty-memorable onions, my Caramelized Onions.

Because, get this, I last made Caramelized Onions for these cousins more than twelve years ago. And yet Sue still remembered them!

A Texan taught me to slice piles of onions for Caramelized Onions: they “made” my homemade fajitas, worth the three hours of slow-simmering on the stove to release a golden-dark, decidedly tasty mess of onions.

But these days, I’ve traded in three hours on the stove for eight hours in the slow cooker.

Why Choose the Slow Cooker for Caramelized Onions?

This summer, I’ve cooked Caramelized Onions four times, testing out the slow cooker three times and then returning to the stovetop once, just to compare.

  • So for years and years, I've cooked caramelized onions on the stove for three hours, checking them every so often to make sure there's still enough liquid in the pot. We don't want onion mush but we don't want burned onions, either!
  • The stovetop works fine, it's a good activity when you’re busy around the house and can keep checking the onions. The only risk? When the onions get close to done, they move from done to burned in a couple of minutes.

  • The beauty of a slow cooker is its low heat, letting you cook hands-off while retaining all the moisture inside.

  • An oven also has even, low heat. And almost everybody has one ...
  • My husband and I are big fans of slow cooking in the oven, you'll see lots of recipes here in Kitchen Parade that use it. It started off because our high-BTU stoves have a hard time holding a low flame. But then we fell in love with slow cooking in the oven! A slow cooker so often just melds everything together into one mush, both in texture and in taste. The oven just doesn't do that, probably because of its controlled temperature, something that doesn't happen with slow cookers, they're just all over the board. So for stews and beans and so many other slow-cooking dishes, "slow cooking in the oven" is often our go-to cooking method.
  • We love the even, stable and consistent temperature control in the oven ... a big improvement over notoriously finicky and unreliable slow cookers. And now? Yes, this technique works for caramelized onions too!

How Long Does It Take to Caramelize Onions?

Okay, I'm going to be blunt here. I think that food writers lie about caramelized onions.

Over and over again, food writers blithely claim that onions caramelize in 10 minutes, 20 minutes, even 30 minutes. In that time, you might be able to sauté onions until deeply, darkly golden. But they're not caramelized, they're just sautéed.

Like good barbecue, real caramelized onions need the "low and slow" treatment, that means cooking them sloooowly over a low temperature.

On the stove, I allow three hours to properly caramelize onions, drawing out the sweetness while retaining the distinct onion structure. No onion mush!

In a slow cooker, I allow four to eight hours, the timing range is needed due to the variability one slow cooker model to the next. Make them once in your own slow cooker and keep track of the timing, then you'll know your own timing going forward.

In the oven, I allow six to eight hours, the timing range is needed due to checking on the onions every so often, releasing the heat in both the oven and the cooking pot.

What To Make With Caramelized Onions

Caramelized Onions are one of those special “building blocks” that make a home cook’s kitchen so productive. For many recipes, you'll use the onions a spoonful at a time.

Here are some ideas! Let your imagination take over, there’s no trouble finding creative uses for Caramelized Onions.

  • Serve Caramelized Onions on the side with steaks, chops, even bison tenderloin.
  • Make roast beef sandwiches, slices of rare roast beef, Caramelized Onions, basil aioli and a few leaves of arugula. These sandwiches were gobbled up at a party this summer!
  • Start a stew with Caramelized Onions instead of sautéing onions. A time saver!
  • Stir a spoonful or two into biscuit dough or a breakfast omelet. A flavor boost!
  • Stir them into cooked broccoli or cauliflower, mash them into potatoes. Re-imagine old favorites!
  • Purée Caramelized Onions with a little vinegar and honey. You’ve got salad dressing!
  • Make an onion pizza! A calorie saver!
  • Make Oaxaca Tlayuda (Flat Tacos)! It’s what fueled my recent obsession with spate of Caramelized Onions.
  • Make Afghan Chicken & Rice Casserole (Kabeli Palau)! One of my favorite casseroles to serve a crowd, it's got an unusual, amazing combination of everyday ingredients.
  • Make Caramelized Onion Tart! This tart uses up to a full three cups of caramelized onions, it's a simple but sophisticated tart with a no-fuss crust that's slightly crisp with cornmeal.
  • I love having caramelized onions on hand, so much that I've started tracking how I use them, check out the onion recipes for more ideas.
  • And you, what do you make with Caramelized Onions? I've got two cups in the fridge, help me use them up!


Hands-on time: 15 minutes plus occasional stirring throughout
Time to table: 5 - 9 hours
Makes 1 cup Caramelized Onions per pound of uncooked whole onions
    Per POUND Uncooked Whole Onions
  • 1/2 tablespoon butter (my preference, for flavor) or olive oil (for vegan)
  • 1/2 tablespoon brown sugar
  • 1 tablespoon white wine, bourbon or dry sherry, optional

In a slow cooker, combine the butter and brown sugar on high until melted.

Peel the onions. Cut in half lengthwise, place flat-side down and slice thin half rings. Stir the half rings into the butter-brown sugar mixture, tossing to coat.

Cover and let cook for 4 - 8 hours on high, stirring occasionally. About half-way through, stir in the liquor.

The onions are “cooked” before they caramelize. For honey-colored onions, cook for shorter time; for dark unctuous onions, cook longer. If any liquid is left once the onions have caramelized, either remove the cover and cook with it off for 10 or 15 minutes (be careful, the onions can burn!) or just use to keep the onions extra moist.

Refrigerate until ready to use. Caramelized Onions keep for a couple of weeks.

SLOW COOKING IN THE OVEN Yes, you can use an oven as a slow cooker! Combine all the ingredients in an oven-safe pot with a tight lid, be sure the butter is melted to distribute well. Slow cook at 225F/105C for up to eight hours, checking every hour to stir, make sure the pot's not run dry, to check the color progression. The first time, take note how long it takes to reach your desired color; the next time, you'll know the exact time in your same environment.

ALANNA’s TIPS Two pounds of onions, that’s about six medium-size onions. After trimming, that yields about 1.5 pounds of uncooked onion half-rings and after caramelizing, yields about two cups of much-condensed caramelized onions. Two pounds perfectly fills my favorite “small slow cooker”, a 1-quart red stoneware "party" crockpot from Hamilton Beach, that, dang it all, is no longer made, total bummer. No problem, four pounds of onions cooks well in a more usual four-quart slow cooker, although honestly, that's a lot of caramelized onions. I do understand that Caramelized Onions freeze beautifully, it’s just not my style. The best onions for caramelizing are yellow, red and white onions. Save "sweet" onions such as Vidalias for recipes where they remain uncooked. Do onions make your eyes water? Yikes, mine too, especially when my contact lenses are out but even, starting on about the third onion, when they’re in. I usually suffer through but enlisting help from the food processor for slicing does help. Save those onion skins! Toss them into a freezer bag and freeze until it’s time to make a small batch of No-Big-Deal Homemade Chicken Stock or a large batch of Homemade Chicken Stock.
NUTRITION INFORMATION Per Quarter Cup: 53 Calories; 1g Tot Fat; 1g Sat Fat; 3mg Cholesterol; 13mg Sodium; 10g Carb; 1g Fiber; 5g Sugar; 1g Protein. WEIGHT WATCHERS POINTS WW Old Points 1 & PointsPlus 1 & SmartPoints 2 & Freestyle 1

More Surprising Recipes for Cooking, Yes, Onions!

(hover with a mouse for a description; otherwise click a photo to view the recipe)

Julia Child's Soubise (Onion & Rice Casserole) Moroccan Onions Spiced Pickled Red Onions
~ more onion recipes ~
from Kitchen Parade

~ Slow Cooker Onion Soup ~
~ Homemade Onion Dip ~
~ Roasted Whole Red Onions with Sweet Potatoes & Rosemary ~
~ more onion recipes ~
from A Veggie Venture, my food blog

Shop Your Pantry First

(helping home cooks save money on groceries)

~ onion recipes ~

~ All Recipes, By Ingredient ~
~ How to Save Money on Groceries ~

Kitchen Parade is written by second-generation food columnist Alanna Kellogg and features fresh, seasonal dishes for every-day healthful eating and occasional indulgences. Quick Suppers are Kitchen Parade favorites and feature recipes easy on the budget, the clock, the waistline and the dishwasher. Do you have a favorite recipe that other Kitchen Parade readers might like? Just send me a quick e-mail via How to print a Kitchen Parade recipe. Never miss a recipe! If you like this recipe, sign up for a free e-mail subscription. If you like Kitchen Parade, you're sure to like my food blog about vegetable recipes, too, A Veggie Venture. If you make this recipe, I'd love to know your results! Just leave a comment below.

© Copyright Kitchen Parade 2013, 2014 & 2019

Alanna Kellogg
Alanna Kellogg

A Veggie Venture is home of "veggie evangelist" Alanna Kellogg and the famous asparagus-to-zucchini Alphabet of Vegetables.


  1. 3FingeredSalute9/25/2013

    Love this idea of using the slow-cooker! As such a versatile food item, you might enjoy playing with the flavor-profile just a touch. I've seen this done with 2 tablespoons of maple syrup and a table spoon of balsamic vinegar (together) for a flavorful zing. Alternatively, you might want to toss in a dried chipotle pepper (or more) to boost the smoky and spicy nature. A sun-dried tomato would give it more of an Italian type of sweetness. Crushed red peppers, used coffee grounds, a few whole cloves (which will render itself down to mush in the slow cooker) of garlic, etc. I'm sure you can think of more wonderful ways to "make it special" and your own!

  2. Anonymous9/25/2013

    Mmmm...carmelized onions and swiss cheese quiche. Can't wait to try cooking my onions this way!

  3. Anonymous9/25/2013

    Great use for leftover slowcooker onions: a friend sent me Alton Brown's homemade onion dip recipe this summer. I'm addicted! So are all the neighbors--great cocktail party dish. Haven't tried it yet with regular mayonnaise. I was using my Dad's homemade mayo all summer, which added extra layers of flavor to everything we made with it.

  4. Why have I not done this yet?

  5. It's funny I'm just getting to this post tonight. Last fall I made your Chicken Cider Stew, and it became the first post in my Food Bloggers Change My Life series. Don't recall seeing it? That's because it wasn't cider season by the time I was ready to post it, so I skipped ahead to the second post in the series, Foodie With Family's Slow Cooker Chicken Tikka Masala last winter. Instead, I put your stew on my schedule for a Monday in early fall, and guess what? That's tomorrow. And my only change to your amazing stew recipe was to start with some caramelized onions, because I had them on hand.
    I'll have to try your method next time!


Post a Comment

Thank you for taking a moment to write! I read each and every comment, for each and every recipe. If you have a specific question, it's nearly always answered quick-quick. But I also love hearing your reactions, your curiosity, even your concerns! When you've made a recipe, I especially love to know how it turned out, what variations you made, what you'll do differently the next time. ~ Alanna