I'm generally a purist when it comes to food—I'll take my burgers with onions and pickles and my cookies with chocolate chips, thank you—but I make exceptions now and then, especially when they involve Brussels sprouts, easily my favorite fall vegetable.
On the menu today: Brussels sprout grilled cheese sandwiches. And ok, we'll go ahead and add some caramelized onions in there as well, because it's cold outside and nothing makes me feel cozy like an apartment filled with the smell caramelized onions.
To get the brussels sprouts sandwich-ready, I first finely shred them so that they meld into the cheese and onions. I use a knife, but a mandolin or the grating disk on a food processor will work as well.
To get 'em nice and sweet while still retaining some crunch, I cook them over crazy high heat in a bit of olive oil for just a few moments until they're charred in spots.
If you're the type of person who keeps caramelized onions in their freezer at all times (you know who you are), you can go ahead and use those, or just proceed with whatever technique you normally use to caramelize onions, including my cheaty 15-minute version. But if you don't want to use that method, a quick light caramelization in a moderately hot skillet will work just fine. The sprouts bring plenty of sweetness to the table, so you don't need to go with the candy-sweet low and slow approach here.
For the cheese, I used a sharp Vermont cheddar (specifically, the awesome three-year-aged cheddar from Grafton Village Cheese, which has a great balance of sharp bite and meltability), though a Comté or an aged Gruyère would be great as well, evoking more of a French onion soup aroma.
I'm perfectly happy with American cheese on white bread (It's the type of sandwich I make most often), but sometimes fancy pants cheese and fillings call for fancy pants bread. I used some slices of a French boule that Ed brought back from Pain D'Avignon in Hyannis, MA. It's good stuff.
You know where you do want to go low and slow? When it comes to actually cooking the sandwiches. The longer it takes for those sandwiches to crisp up in butter, the more evenly they'll brown, the better crunch they'll get, and the meltier the innards will be.
Pressing down on the 'wiches with a pan as they cook will also help them acquire a more even, crisp crust. It should take at least 8 minutes to properly cook a grilled cheese sandwich, though longer is not unheard of.
(Though to be honest, it looks like I might have cooked this one a little bit too fast. See how the center is darker than the rest? Oops.)
I really love the way the charred Brussels sprouts work with the buttery crust and sweet onions in this sandwich. Even my wife wolfed hers down without complaining about the dogs smelling like onions (as she usually does when I caramelize onions at home). Looks like this one's going to stay on the menu here for a while.
About the author: J. Kenji Lopez-Alt is the Chief Creative Officer of Serious Eats where he likes to explore the science of home cooking in his weekly column The Food Lab. You can follow him at @thefoodlab on Twitter, or at The Food Lab on Facebook.