Thick-cut braised-then-crisped pork belly is one of the easiest things in the world to cook. Seriously. You could throw the pot of it in a low oven, leave, find all 96 stars in Super Mario World, head out to a Star Wars marathon—including the episodes-that-shall-not-be-named—come back, and you'd still be able to take a bath before dinner and have something juicy and delicious waiting for you. Ok, that's probably not true, but what is true is that just about the only really terrible thing you could do to a slab of pork belly is to undercook it.
So why, you might ask, would one resort to cooking something so fool-proof using a newfangled method like sous-vide?
Two reasons. First, sous-vide ain't so newfangled. Where'd you get that idea? These days, sous-vide equipment is cheap, reliable, and increasingly becoming a staple in the modern kitchen (give it five years—mark my words). Second, if pork belly cooked through regular means is regular Mario, pork belly cooked sous-vide is Mario with a fire flower and an invincibility star. If regular pork belly is a hot dog, then pork belly sous-vide is a million hot dogs. If regular pork belly is you thinking you're clever for propping up the wobbly table with a folded coaster, then pork belly sous-vide is MacGyver building a bomb out of a tuna fish sandwich and a bobby pin.
I know people have a thing against using the word unctuous to describe food, but that's what pork belly cooked sous-vide is. It starts out as a solid slab of meat; then, when it hits your tongue, it melts into a creamy, tongue-coating wash of pork fat. It's not food for the faint of heart. Cram it into a soft-steamed Chinese-style bun with a few carefully concocted condiments, and you've hit on one of the greatest appetizers ever conceived.
Here's how I like to do mine.
I use a very basic Japanese-style braising liquid for my pork belly—similar to what you'd find in the classic simmered pork belly dish buta no kakuni. At its base are soy sauce, mirin, and sugar, all in equal volumes. To up the umami factor and bring out the meatiness of my pork, I also add a quarter part of fish sauce.
Typically, for kakuni you'd need a fair amount of liquid. With the sous-vide approach, you only need a little, since it all gets pressed around the pork in the vacuum-sealed bag.
For aromatics, I stick with the holy East Asian trinity of ginger, scallions, and garlic. Everything gets whirled together in the food processor.
Pro-tip: When putting moist items into a vacuum sealer-type bag, fold back the top lip over your hand so that it stays clean. This will help you get a better seal down the line. For the pork belly itself, you can use one giant slab, or, if you can't find one, use a couple of thinner slabs like I did here. No matter what, you want to go at least an inch or two thick.
Food Saver-style sealers aren't fantastic at sealing moist items, as the liquid tends to seep up into the machine. There are a few solutions to this. Some folks advocate freezing your liquid into small cubes or flat sheets before bagging them. I find it easier to just work over the edge of a counter, letting the bag hang down out of the sealing device (make sure you support it!) so that all of the air rises to the top naturally. As soon as the air is sucked out and the liquid starts to get squeezed, hit the seal button and you should get a nice, air-free bag with very little liquid leakage into the machine's liquid trap.
Use a paper towel to wipe out and liquid that might have escaped (you don't want this gunking up your circulator).
Then, press the belly to make sure that it's evenly coated on all sides with the marinade.
There's more than one way to cook pork belly in a sous-vide machine, and to decide on how to do it, you've got to understand the relationship between temperature and time.
For cuts with lots of fat and connective tissue like pork belly or, say, short ribs or spare ribs, the goal is to get all of that tough connective tissue (mostly collagen) to convert into rich, sticky gelatin, forcing the meat into tender submission.
With traditional cooking methods like braising, slow-roasting, or confit, you don't have great control over temperature. Usually, you end up having to do it hotter than is ideal. At higher temperatures, connective tissues break down faster, but you also end up forcing muscles to squeeze out more liquid.
With sous-vide, you get the best of both worlds—the control to be able to tenderize connective tissue without having to get so hot that your meat dries out.
Some folks advocate ridiculously low temperatures and long time combinations—72 hours at 150°F (66°C). With pork belly, this can be a little overwhelming—you have to really love gelatinous meat to enjoy the texture. Sometimes I do. I advocate a 155°F 36-hour cook for my Deep-Fried, Sous-Vide, All-Belly Porchetta.
But in this case, I'm going with the more reasonable 170°F (77°C), 10 hour combination. This makes it just right for setting up in the morning and taking out when you get home from work, or setting up in the evening and removing when you wake up in the morning. It also gives you pork that's plenty tender and moist, but with a slightly more "traditional" texture.
When it comes out, chill it so that you can easily remove the hardened fat. At this stage, you can leave it in its bag in the refrigerator for weeks—it's all sterile inside from that long, slow cook!
If all went well, the cold meat should have a soft, almost buttery texture when you slice it into chunks for broiling.
And what about all that extra liquid in the bag? Surely we're not going to throw it away, are we? Not only does it have all the flavor of the original marinade, but it picked up plenty of pork juices during its cook as well. No point in wasting it.
Instead, I incorporate it into a sauce by first straining it, then reducing it on the stovetop into a thick syrup. Just be careful not to burn it—all that sugar and the pork proteins are inclined to stick to the bottom of the pan.
Once it's reduced, I stir it into some homemade mayonnaise.
I've been trying to come up with a name for this rich, sweet, intensely meaty stuff. Pork braise mayo is appropriate, but not quite sexy enough. Meat-tastic Porkalicious More-Than-Mayo Magic Spread perhaps? I'll take suggestions if you've got 'em.
As with all things sous-vide, the pork has no real texture other than soft when it emerges from the cooker. To add that, along with a bit of browned and caramelized flavors, I turn to the broiler. The slices of pork belly take just a few minutes to crisp up.
Fair warning: once it gets sizzling, that pork belly is going to spit more than Alice Waters at a Monsanto party, so be careful when you retrieve it. Wear an apron, perhaps some safety goggles, and stand back until it cools slightly.
I would offer you my recipe for homemade steamed buns, but frankly, my recipe stinks. The ones you can buy at the Asian grocery store in the refrigerated or frozen sections are vastly superior, especially when you reheat them in a real bamboo steamer. Like Martin's Potato Rolls, ramen noodles, and sensual massage, some things are just better left to the professionals. For now.
Pickles, on the other hand, are something you can make better than store-bought at home. Much, much better. For applications like this, I like to use a quick, 15-minute pickle like these ones here. They retain a bit of fresh bite and more of their crisp, light, cucumber flavor. Rice vinegar and sugar add just a touch of acidity and sweetness to them.
The lettuce is not particularly necessary for flavor, but I do like to add it in order to cradle the pork and prevent it from completely saturating the bun in the fat that will start to drip out as you bite into these. And you will bite into these. Again and again and again.