Upgrade Your Grilled Cheese with Beef Stock Infused, Caramelized Onions

When you slice through and break open the cellular structure of an onion, an irritant called syn-propanethial-S-oxide, a sulfuric compound, triggers your lachrymal glands to release tears, is introduced to the atmosphere. This isn’t so bad if you are only working with a small amount of onions. However, when doing lots of chopping and slicing, like with this recipe, the waterworks can really get in the way of your prepwork.

Here are some tips that can be used separately or all together.

–Sharpen your knives. The sharper the knife you use to cut your onions, the less cells are broken and sulfuric compounds are released.

–Decrease the exposure of cut onion surfaces to air. Keep the cut sides of the onion face down on your cutting board as you cut. In addition to stabilizing your onion, this will help a bit with tears. After each section/onion cut, move the onion pieces to a covered plate or lidded container. Also, wipe down your board and your knife after each completed section/onion, to soak up the liquid released from slicing through the onion.

–Use a kitchen vent or fan. Cut your onions under a kitchen vent or fan. It helps clear the air of the sulfuric compounds in onions that cause you to cry.

–Wear protective eyewear. Okay, yes for those of you without contacts, this could look ridiculous. But, if you do have the option of slipping in contact lenses, you’ll immediately add a mostly impermeable membrane over your eye. Viola, no tears! Fore everyone else, it’s goggles for ultimate protection, sorry. You can still choose to look cool next to a fan and work through a little bit of tears. No judgement.

So this is mostly about flavor. Each listed onion has different flavor profiles and add depth that would otherwise be lacking if you used only one type of onion. This difference is obviously more prominent when the onions are uncooked, however the sugar content and underlying flavors do subtly carry through the cooking process.

I suggest using sweet onions (think vidalia or walla walla onions) if you only plan to purchase one type of onion for this recipe. Their sugar content makes them ideal for caramelization. Use the flavor descriptions above to mix and match for your own special blend of onions. Just make sure to keep the overall measure of alliums the same in the recipe.

This recipe uses yellow onion, white onion, sweet onion, and a shallot. Let’s take a look at each one, yeah?

Yellow: Yellow onions have a brownish-yellow papery skin and a yellowish-white flesh. They are stronger and more pungent than other types of onions and offer just a slightly sweet taste. If you ever see Spanish onions and wonder where they belong, they are a type of yellow onion, but are larger, milder, and sweeter than their smaller counterparts.

White: White onions have white, papery skin and white flesh. These onions are crisp, slightly tangy, and cleaner tasting than yellow onions.

Sweet: Sweet onions have yellow or light brown skin and white, juicy flesh. They are are known for their high sugar content and mild, sweet taste. The flattened disc-like shape of vidalia onions are most commonly associated with sweet onions, but that is actually specific to vidalias. Sweet onions can also be spherical like any other onion.

Shallot: Shallots have a brownish-red or grayish-brown outer skin and white, pink, or purple flesh. They have a delicate, mild onion and garlic flavor with a light, slightly sweet taste.

BONUS ONION: Red onions have a deep purple outer skin and red/white flesh. They mild enough that they can be eaten raw and have a slightly peppery taste. I didn’t use these onions in the recipe, mainly because they would have slightly colored the filling. Also, white onions have the same clean taste as red onions, just stronger. If you like red onions, and aren’t worried about visuals, go ahead and use them!

Caramelization is a chemical process that occurs when sugar molecules are heated to a high temperature, causing thermal decomposition. Essentially they break down and then undergo a series of complex reactions that form new compounds to produce a range of flavors, colors, and aromas.

During caramelization, heat causes the sugar molecules to break down into smaller molecules, which then react with each other to produce a range of volatile compounds, including furans, pyrroles, and aldehydes. These compounds are responsible for the characteristic flavors and aromas associated with caramelized onions, such as sweetness, nuttiness, and smokiness.
At the same time, the Maillard reaction occurs, which is a reaction between amino acids and reducing sugars that also produces a range of flavorful compounds, such as melanoidins. This reaction creates the brown color and savory flavor that is associated with caramelized onions.

Lower heat allows for even cooking and better flavor. If the onions burn, it will introduce a bitterness to your final product. If you see any burning either the liquid made by the onions or the onions themselves sticking to the pan, deglaze with the beef stock as quickly as you can and lower your stove top temperature.

You may be tempted to try and cut down on your cook time by increasing your cooktop temperature Yes, your onions will brown faster. However, metaphorically, this is like speeding on the highway. We all do it and we could get where we are going a few minutes faster, but there might also be negative consequences to our actions if we aren’t careful or watchful. It’s easier to just play by the rules sometimes, because starting over is a penalty of both time and money.

First things first, I used aged gruyère (at least 12 months) and fontina cheese for these caramelized onion grilled cheese sandwiches. Let me give a quick brief on why I chose them.

1. Gruyère (swiss cheese) is the traditional cheese topper for onion soup, so I knew I wanted to keep that sweet, nutty flavor in this recipe. I tried different gruyères aged from 3 months to 12+ months. The 12 months + gruyère was far more flavorful and the nuttiness really punched through the onions in a way that it’s younger counterparts didn’t.

2. Because, gruyère doesn’t stay melty for very long, I added in fontina to take care of that textural component. Fontina is very mild in flavor as well, so it didn’t interfere with the flavor of the gruyère.
Of note: The 1:1 ratio of these cheese gave me the best texture to flavor balance, but you can definitely experiment with different amounts.

Here’s a list of some other cheeses that could work in a caramelized onion grilled cheese sandwich.

1. Havarti – mild, buttery, and tangy (melty)
2. Provolone – mild, nutty, and tangy (melty)
3. Monterey Jack – mild, buttery, and sweet (melty) – pepper jack for a kick! 😉
4. Goat/chèvre – tangy and earthy (creamy)
5. Brie – earthy, buttery, and nutty (gooey)
6. Cheddar – tangy, salty, and sharp (creamy)

In the name of transparency, I also tested the gruyèye with gouda and havarti in this sandwich during recipe development. The gouda was a little too strong for what I was going for. I really wanted the gruyèye to stand out and gouda wasn’t allowing that. So, decide what you like and what flavors you want to pop when you choose your cheese.

Yes, of course! Other breads I’d recommend are rye bread or some kind of rustic white bread. As long as the bread is hearty and can hold up to a heavy filling, you’ll be good to go.

I’m sure most of you have seen the grilled cheese flipping hack video online, but I’m here to say, it works!

Essentially, you take your flipper/turner (what you would use to flip pancakes) and slide it under the sandwich so it’s between your grilled cheese and the pan. Make sure you have enough stability, that when you take the pan away, it can hold the grilled cheese in the air without issue. Now, remove the pan from under the flipper and sandwich and press it to the top of the sandwich, so the sandwich is now in between the pan and the flipper. Turn, everything over together. Now, your pan is on the bottom, the other side of the sandwich is on the cooking surface and the flipper is on top. By using this technique, the sandwich movement is minimal and there is less chance of the bread sliding around or the cheese/filling falling out.