You're One Ingredient Away From Truly Luxe Grilled Cheese

We've covered a whole panoply of grilled cheese mistakes you might be making, but one biggie springs to the forefront: not maximizing added ingredients to your toastie to make it truly indulgent. One item, in particular, elevates a humdrum grilled cheese from "quickie lunch" to "luxurious handheld," and (other than time) it will cost you very little to incorporate. That would be caramelized onions.

Caramelized onion grilled cheeses have taken the internet by storm, showing up among epicures as diverse as those on social media and newspapers of record. Honestly, we're wondering why we didn't think of this sooner. We love French onion soup, to which sweet, umami grilled cheese with caramelized onion owes a debt of lineage. We also love patty melts, the best part of which is the way that soft slivers of onion get lost in gooey cheese. It's a natural pairing, one that the culinary gods fully intended for man to happen upon.

We can quibble endlessly about the best breads for grilled cheese and, of course, the cheeses that should star in its middle, but, honestly, there's no wrong answer here. A nutty Gruyère or Swiss will steer your grilled cheese directly into French onion soup territory — honestly, a good place to be. For our money, we like both bread and cheese that can pull their weight against sweet, succulent onions ... think thick-sliced sourdough or multi-grain. An onion jack cheese would be delightful when grated over your sando — and shredded cheese absolutely belongs on sandwiches for the best melt — but we wouldn't be mad about classic white American, either.

There's one obvious downside to a caramelized onion grilled cheese, but it's a biggie: onions take so, so long to caramelize! Regular sautéed onions are delicious, but they have too much residual crunch and strong flavor when you really want the sweetness and jammy consistency of caramelized onions. Properly caramelizing onions can be a 45-minute exercise in stirring, temperature control, and patience. When you want grilled cheese, waiting three-quarters of an hour before you can even butter your bread isn't always doable.

One option is to check out chef-approved ways to speed up the caramelization process. America's Test Kitchen, an undeniably solid source, recommends two alternative methods for halving the time to caramelize onions. One involves adding a splash of water and covering the skillet so that steam can work its magic on breaking down the onions. Another uses a sprinkle of baking soda to speed browning. No matter what you do, don't be tempted to simply jack up the heat and rush your process. All you will do is burn your onions and delay lunch even further.

Another respectable option for caramelized onions practically on demand is preparing a big batch and freezing them for later use. Caramelize your onions as usual, then portion them into either an ice cube tray lined with plastic wrap or individual muffin cups. Once you flash-freeze your onions for a couple of hours, remove the frozen pucks from their containers and store them in an airtight freezer bag. Just thaw a puck or two when you're ready to ascend to Grilled Cheese Paradise!