Question: What’s the easiest way to make caramelized onions?
Answer: In a slow cooker. Just “set it and forget it” as they say.
Believe it or not, onions are naturally sweet and the longer you cook them, the more the natural sugars come out. Eventually, those sugars will caramelize and the onions will become sweeter, almost like a jam. I’ve seen caramelized onion recipes that call for sugar, or add balsamic vinegar, but really, you don’t need anything but the onions, some oil or butter to cook them in, plus some salt and pepper. If you need to add sugar, “yer doin’ it wrong!” (This last bit must be said with a heavy Scottish accent.)
Of course, you can caramelize onions in a pan over very low heat, in less time than in a slow cooker, but this takes attention to make sure the onions don’t cook too fast or burn in the process. If you cook them on too high heat, they may burn before they get sweet. You need to watch them at all times. In a slow cooker, you can take a peek every every few hours, or even ignore it overnight, and get the same, if not better, results.
In the photo above, clockwise from the top left; cut onions, cut onions with oil, salt, and pepper added to the slow cooker, after cooking for four hours, and after cooking for 12 hours in the slow cooker.
Caramelized onions are great on sandwiches (think patty melts, cheesesteaks, roasted pork, grilled chicken), in pasta, in baked dishes like a quiche, casserole, or savory tarts. The list goes on and on. I hope to have some new recipes where you can utilize these deeply flavorful onions coming soon!
The challenge in cooking with caramelized onions as an ingredient is that making them every time you want a little bit is a pain when you just want to complete the dish. You’ll need to cook the onions for an hour or more on very low heat to get the results you want.
Make a big batch and save time later:
No matter how you choose to make them, in a slow cooker or skillet, I highly recommend you make a large batch and portion them out in smaller amounts for later use. You can put them in anything from ice cube trays to small Tupperware or you can try something like the silicon Souper Cube tray below.
I received both the half cup and full cup sizes of Souper Cubes as Christmas gifts (does my family know me or what?) and they are a fantastic way to freeze sauces, stocks, soups, and yes, caramelized onions. The half-cup Souper Cubes were perfect for this recipe. Once they were frozen, I popped them out of the container, wrapped each frozen cube in plastic wrap, and put them in a freezer bag. I’ve already used one block for an eggplant recipe from Ottolenghi’s cookbook Simple that called for caramelizing an onion. What a time saver!
The easiest way to make caramelized onions, in a slow cooker
Prep Time10 minutesmins
Cook Time12 hourshrs
Total Time12 hourshrs10 minutesmins
Course: Condiment, Sauce
Keyword: caramelized onions, onions
3poundsyellow onionssliced thin, about 4 each
2tablespoons extra virgin olive oil
½teaspoonblack pepperfreshly ground
Peel the onions and cut them in half. Thinly slice them crosswise.
Place the sliced onions in a bowl and toss them with the olive oil, salt, and pepper.
Place the onions in the slow cooker, turned on low. Cook for 4-5 hours and then check and give them a stir. You can also put them in when you go to bed and let them cook overnight. They will take 10-12 hours to get to the caramelized (sweet and brown) stage.
If after 10-12 hours, they have too much liquid in the bottom of the pot, let them cook for 30 minutes to an hour with the lid ajar so that some of the moisture evaporates.
When the onions are done, cool and refrigerate or freeze. See notes on freezing below.
Caramelized onions should keep for up to 14 days in the refrigerator or up to 6 months in the freezer.I highly recommend Souper Cubes for freezing sauces, soups, and yes, even caramelized onions. I froze them and then popped them out, wrapped them in plastic, and packaged them up for later use.
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