The Best Cast Iron Cleaner Might Already Be on Your Kitchen Counter

There’s a lot we love about cooking in a cast-iron skillet. It retains heat beautifully, giving steaks and burgers a beautiful sear and cornbread a perfectly crispy crust. What don’t we love as much? Scrubbing the skillet afterward to remove the stuck-on bits, then seasoning it to restore its glossy coat. But what if there was a way to skip both, and make something truly delicious in the process?

Thankfully, there is. By using your cast-iron skillet to caramelize onions, you’ll pick up any bits left in the pan, and simultaneously restore its nonstick finish. Now that’s a cleaning job we’re happy to tackle. 

How Caramelizing Onions Helps To Clean Cast Iron

Onions have a high water content. That’s why a large amount of onions cook down to a fraction of their size when caramelized. Gradual cooking over low heat releases moisture, loosening the stuck-on bits—also known as fond—in your pan. The fat you’ve added to the skillet to cook the onions will help season its surface, remove any rust stains, and restore its glossy finish.

What Is Fond?

If you’ve ever seared a steak in a hot skillet or browned pieces of chuck roast in a Dutch oven before stewing, you are likely familiar with fond. Fond is a culinary term for the browned bits that are left in the pan after searing meat. These browned bits are full of flavor, which is why many recipes tell you to deglaze the pan to loosen and incorporate them into your dish. These bits are what you’ll want to scrape up from your pan as the onions caramelize.

How To Caramelize Onions

Heat your cast-iron skillet over medium heat. Thinly slice two large yellow onions. Add two tablespoons of butter or olive oil to the skillet. Add the onions, season with salt, and cook, stirring occasionally, until golden and jammy, 30 to 60 minutes. If the onions are browning a little too fast, lower the temperature slightly and add a splash of water. At the end of cooking, add another splash of water to loosen any browned bits.

When Not To Use This Method

You won’t want to caramelize onions to clean your cast-iron skillet if any of these three situations apply: 

• You don’t have much time: Caramelizing onions often takes up to an hour. If you’re not already busy in the kitchen or can’t keep an eye on the stove, skip this method. 
• Your skillet has been sitting for a couple of days: The caramelized onions will pick up whatever is in your pan. If you’ve left the skillet uncleaned for more than a day, there’s a risk that the residue could impart some off-flavors to your onions.
• Your skillet needs more serious TLC: If it’s significantly scorched on the bottom, caramelizing onions won’t be as effective (and they’ll taste like whatever you burned the last time you used it). Instead, give it a good cleaning and season it to restore the cooking surface. 

How To Use Caramelized Onions

Caramelized onions are a great way to add a boost of flavor to anything you’re cooking. Whether you’re stirring caramelized onions into creamy pasta, blending them into a creamy dip, or stuffing a grilled cheese sandwich with them, there are countless ways you can incorporate jammy onions into a recipe. And now that I know it’s possible to clean my cast iron while cooking something delicious, you bet I’ll be making this my go-to method for restoring the shine on my skillets.