45-Minute Perfect Caramelized Onions + Quick Onion Gouda Rolls

Remember when we talked extensively about allium defenses last week? Well I decided to roll with it and share more onion fantastic-ness. More specifically, I’m writing about my perfect caramelized onion how-to. Just for you!

When I was younger, I never knew the joy of caramelized onions. I might have been too picky to try them, who knows. But I am now truly sad I missed so many years of onion magic! For past five years, I’ve tweaked and tested my technique. There are countless blogs and articles that postulate the BEST caramelized onions you’ve ever had in ranges of 5 minutes to 5 hours. What is the real deal?! Well I’m here to share my experiences and how I settled on this method. Plus, I pulled on some science background to get the top-notch result you see here.

First, let’s revisit what a caramelized onion is. It’s a cooked onion that softens and browns rendering it utterly delicious and slightly sweet. But the wordplay there is a bit misleading. There are two major types of non-enzymatic browning that we talk about when we’re geeking out about food: caramelization and Maillard browning. (The enzymatic browning is caused by the enzyme polyphenol oxidase and occurs in more unwanted situations like cut avocados and apples)

We chatted a bit about the difference between caramelizing and Maillard when we made French Onion Soup several years ago (still a stellar recipe, but I think it would be improved with this updated onion instructional!). Caramelized onions are not actually caramelizing when we prepare them, so it’s a bit of a misnomer.

Now that we’ve covered that, the next step is to go over the basics and science behind this method. The essential overview is that we slice onions up, add them to a heavy pan with some oil, and cover the pan with its lid. Then, a liquid is added periodically to deglaze and rehydrate the onions followed by a tiny addition of baking soda and final concentration of the onion mixture uncovered. Sound good? Good! Let’s break it down.

First, let’s discuss the two major parts of this process: the softening and the browning.

The softening is relatively simple. We want to sweat the onions out and cause the cellular walls to break down which accomplishes two things. Most familiarly, the stiff, crisp onions become limp. That’s the recognizable bit. The second part is fascinating. As the heat breaks down the cell walls within the onion, the water and other components like natural sugars and proteins within the onion are released and ooze out. The water prevents the onions from drying out initially over the stove’s heat, and it also becomes important later as we hope to accelerate the browning of the onions. The released sugar likewise plays a role later on.

This method uses a lid in the first half of the procedure. That’s because we want to maximize the softening. It ensures the moisture from the onions condenses on the lid and drips back down into the pan allowing the onions to continually soften. We also take this opportunity to add additional water as the onions cook periodically to be absolutely sure they’re not drying out under that lid. If the onions crust over by browning really quickly on the outside (like a steak sear), the onions will be essentially sealed, and we’d have to do a bunch more softening work to make sure they are recovered at this point. One final mention with this method is that higher temperatures cause the browning reaction to happen more quickly. If we keep some water around, we can crank the temperature a bit from low to medium-low without burning the onions. More water + higher temperature = softer onions = optimized Maillard browning overall.

Now for the second major half of this. The actual browning. I mentioned earlier that the release of water from the onions is important. That’s because Maillard browning as a chemical reaction is optimized under a low-moisture environment. When we get rid of a lot of excess water from the onions, we put our finger on the scales in the direction of browning. Once we soften the onion, we take the lid off and let the water evaporate. The result is that a majority of the water from the once intact onions disappears but leaves the resulting cooked onions luscious after all the softening they went through.

The other parts of the equation are the nutrients required to make the reaction ‘go.’ Reducing sugars like glucose and amino acids from protein are the ingredients to the recipe for browning compounds. The natural sugars and proteins from the onion, once released, start to go at it and brown, brown, brown as the heat pushes them forward from below.

There is one more way we can manipulate Maillard. It’s pH. The reacting sugars and amino acids are more optimized when the pH is closer to basic levels (i.e. above pH 7). Food is pretty universally acidic, so if we want to get browner onions faster, we can add one more ingredient—baking soda. Baking soda, or sodium bicarbonate, is a basic food ingredient. Just a pinch changes the pH slightly speeding up the process a bit without affecting the flavor. But be careful! Too much will lend a metallic flavor.

Science!

Looking for more Maillard science fun? Check out this video I made with my good friend and fellow grad student Charlene Van Buiten early in 2016. We were planning on collaborating with Kwame Onwuachi, a fabulous inspirational chef, to combine science and fine cooking in a web series. He loved it, we loved it, but it didn’t end up working out. On the bright side, now we have this fun (only slightly cringe-y) vid from pre pre pre planning. (PS we still love you Kwame! Would still love to collab one day!)

There are several parts of this caramelizing process that I do personally in my kitchen to make it even more foolproof.

First, I use a heavy, cast iron Dutch oven.

Cast iron heats more evenly than other materials and thus avoids hot spots you sometimes get with nonstick skillets. The heavier lids also protect the first part you read about above by trapping the water.

Second, I like to cut the onions in the direction of axis to axis.

I.e. the knife points from the tip of the onion to the root cutting across, starting from the side of the onion and ending at the other side. This is a trick I picked up from Kenji of Serious Eats. The most common way home cooks do it (including me) is to cut with the knife perpendicular to the axis of the onion—the same position you use to dice the onion. If you cut along the axis, the onion pieces are more uniform in size, and the texture will be superior. An onion sliced perpendicularly can sometimes be ‘wormy’ in texture and tougher as you rupture different cells when you go against vs. with the grain of the onion.

Finally, instead of using water as the liquid I add during step one, I use apple cider.

There are multiple reasons for this. One is that if we add a bit of sugar externally (i.e. in addition to the inherent sugar in the onion), it speeds this whole thing up immensely. We create 10x the reactions as the sugar breaks down and participates in the browning reactions on its own. Another is the neutral, yet fresh flavor. Most other juices or sugary potential additions are stronger in flavor and could overpower the onions. Finally, I like to use cider because of its natural pectin content. Pectin can be helpful here with final texture. It helps firm up the final product like a jam and prevents the onions from being too loose or watery—especially if you’re storing them in the fridge for a bit. The pectin also helps once we add the baking soda. Baking soda can be destructive and break down the texture of the onions in an unpleasant way, making them mealy. The natural apple cider pectin supplements that and keeps the whole thing from falling apart.

Feel free to use something else—even water like I mentioned above. You may need to increase the cooking time a bit to get the same results. I’m going to get so much heat for this, but a cheap flavorful alternative is ketchup. Mix 1-2 tablespoons of ketchup into a cup of water, and you’ll have savory wonderful-ness. Ketchup also has a lot of sugar and texturizing agents similar to apple cider.

Okay, this is becoming a novel. Let’s get to the recipe, shall we?

But wait, there’s more! I know that not everyone is a big fan of eating caramelized onions by the spoonful out of the fridge, so I’ve got a few recipes they would be fantastic to use them in from the blog, pasted below. I also retooled my quick sweet espresso rolls with a caramelized onion filling and included this beauty below as well. It’s got onions and cheese and sesame seeds and poppy seeds, so it’s basically an everything bagel roll—ready in an hour. Drool. Enjoy friends!

45-Minute Perfect Caramelized Onions

Makes ½ cup

Print Recipe

¾ pound sliced onions, about 4 medium onions (details above, take weight after slicing) Note: I like to use a mixture of yellow onions and shallots here whose flavors blend nicely, but feel free to use whatever you like!

2 tablespoons olive oil

1 cup apple cider (details above)

⅛ teaspoon baking soda

¼ teaspoon Kosher salt

In a heavy pan or Dutch oven, heat the oil over medium-low heat. Once shimmering, add the sliced onions. Heat, stirring every thirty seconds or so, until the onions are fragrant and steaming, about 5 minutes.
Put the lid on the pan and heat for five minutes. Take the lid off and stir. If the onions are sticking to the pot and pre-maturely browning, reduce heat to low. Add a quarter of the apple cider to the pan, stir to combine, and replace the lid.
After 8 minutes, take the lid off, add another quarter of the cider, stir, and replace the lid. Cook for another 8 minutes and add another quarter cup of the cider. Stir and return the lid.
After 8 more minutes, add half of the remaining cider (⅛ cup), stir, and cook for five minutes. Stir the baking soda into the remaining cider.
Take the lid off of the onions and stir. The onions should be browning and softened. Set the lid aside.
Add the cider/soda mixture and stir to combine. Add the salt as well. If you reduced the heat earlier to low, increase to medium low. Continue stirring every twenty seconds. Heat and stir until the liquid evaporates, about five minutes.
At this point, you’ll want to stir continuously to avoid scalding. Continue to cook the onions, stirring, for another 5-7 minutes. The onions will turn a deep, jammy brown. And that’s it! Use within a week if you seal well and keep in your fridge.

Tip: If you like onion-y pasta, deglaze the pan with pasta water to make a sauce, add cooked pasta, and top with cheese and/or yogurt. Enjoy!

Quick Onion Gouda Rolls (AKA faux-everything bagel rolls)

Makes 12 rolls

Print Recipe

Adapted from here

Dough

½ cup whole milk

2 tablespoons unsalted butter

1 tablespoon granulated sugar

1 ½ teaspoons instant yeast

1 ½ cups flour, plus more for dusting

1 large egg yolk

1 tablespoon Worcestershire sauce

Filling

¼ cup unsalted butter

1 teaspoon paprika

3 dashes Worcestershire sauce

1 recipe (½ cup) caramelized onions above

1 oz gouda cheese, shredded

For topping

1 tablespoon poppy seeds

1 tablespoon sesame seeds

Flaky sea salt, such as Maldon or fleur de sal

Start with the dough. Combine the milk, butter, and sugar in a small saucepan. Stir over low heat, cooking just until the sugar dissolves and butter melts. Remove from the heat and cool until the mixture is just warm to the touch.
In a large bowl, pour the now-warm milk mixture. Sprinkle the yeast over the top and swirl to incorporate. Set aside in a warm place for 5-7 minutes until the mixture is fragrant and the yeast is activated. You may see some slight foaming on the top.
To the bowl, add 1 ½ cups flour and egg yolk. Stir together with a wooden spoon or rubber spatula, but just until it’s halfway mixed. Add the Worcestershire sauce and stir until it all comes together. If the dough is wet, add another tablespoon or two of flour. (you don’t want to add the Worcestershire directly to the milk/yeast mixture because the salt could kill the yeast and curdle the milk)
Knead the dough with your hands in the bowl a few times to bring the ball together. Do not over-work here. It should not be springy, but soft. Cover the bowl with plastic wrap or a damp tea towel and let sit in a warm place for ten minutes.
While waiting for the dough to rise, prepare the filling. Melt the butter in a small bowl and add the paprika and a few dashes of Worcestershire sauce. Set aside.
On a lightly floured surface, dump the dough ball out of the bowl. Roll into a rectangle approximately 9×12 inches in dimension.
Spread the melted butter mixture over the dough, leaving a half-inch uncovered border around the outside. Top this with the caramelized onions evenly followed by the shredded cheese.
Roll the dough into a coil on the longer edge (aka the hot dog way, not the hamburger way)
Use a sharp knife or a length of string to cut the coil into 12 pieces. Feel free to cut away the very edges that have no filling.
Spray a 9×9 inch baking pan with cooking spray. Place the roll pieces into the pan, equally spacing between them. Sprinkle the tops with the seeds and a few pinches flaky salt. Cover the pan with plastic wrap or a damp tea towel and let rise for 30 minutes in a warm place, or until slightly swelled. The rolls should be grown in size, but not quite doubled.
While waiting for the rolls to rise, preheat the oven to 350°F. Move an oven rack to the middle position.
Once risen, uncover the rolls and bake for 20 minutes, or until golden brown, rotating the pan at 10 minutes.
Take the pan out of the oven and let cool until just warm to the touch. Enjoy!
If saving for later, cover the top of the pan with aluminum foil and refrigerate. To reheat, heat the rolls in a 300°F oven with the foil on until warmed through. Check after 10 minutes and then every 4-5 minutes after that. Use a finger to touch the side of a roll at the center of the pan to check for complete warming.