Chāshū is my favorite meat ingredient for ramen. Just like ramen, it came to Japanese cuisine from China and transformed into a very different dish. Originally, char siu 叉燒 is a kind of barbecued pork in Cantonese cuisine. In Japan, it is meaty pork belly slowly cooked in a flavorful broth. At the end of cooking, pork belly loses a lot of fat and becomes very tender and soft. Every bite of chashu melts in the mouth. For ramen, chashu os served thinly sliced. A very similar Japanese recipe for pork belly to serve it with cooked rice, hot mustard sauce, and pickled vegetables is called Buta no Kakuni (豚の角煮, “pork cut square and simmered”). For both recipes, pork belly can be skinless or with pigskin, based on personal preferences and availability.
Chāshū is famous for its amazingly tender, melting in the mouth texture and highly appealing aromas. Even though we start making it with one of the fattiest cuts of pork, a lot of fat is rendered away during the cooking. It can be slowly rendered on a dry skillet (see instructions in the recipe below) or boiled with okara, soybean pulp left after straining soy milk. Slowly is the key word here. The ratio is about 5-6oz of okara to 1lb of pork belly. In a pot, cover pork belly portions with cold water 1″ over the top of the meat and stir in the soybean pulp. Bring water to boiling, reduce the heat, and simmer for 2 to 4 hours. Cool the contents of the pot to room temperature and then refrigerate to solidify the fat. Carefully remove pork pieces, rinse them with warm water, and cook in a flavored broth.
Using stove at the beginning and oven at the end is the probably the most widely accepted way of cooking pork belly, but slow cookers are obviously are perfect devices for the task. Sous vide also comes to the mind, though the only advantage it gives is using cooking broth more economically. It is, naturally, a perfect way of cooking lean cuts (e.g., pork loin) with chāshū flavor.
Peel garlic. Peel and slice ginger 1/4" thick. Wash scallions and cut off the root ends. Turn on the oven to preheat it to 325F.
Cut pork belly to ~5" L x 2.5" W x 3" H blocks. Arrange them on the bottom of a cold skillet and place over low heat to slowly render fat.
It should take about an hour, doing it on all sides. Collect the fat to use for cooking other dishes and refrigerate or frezze. Pat dry cuts of pork belly with paper towel.
To make a cooking broth, combine the rest of ingredients and bring them to boiling, stirring. Turn off the heat, place pork belly cuts into the broth, cover with foil and place in preheated to 325F oven.
Cook for 3 hours. When pork belly is done, transfer it to containers and cover with strained broth. They should be fully submerged. Refrigerate until ready to serve. Slice cold or slightly frozen.
for sous vide pork loin chashu
Peel and thinly slice garlic and ginger. Wash scallions, cut off their root ends and chop the rest. Preheat water for sous vide to 140F/60C. Cut pork loin into three portions 1lb/500g each, tie them tight, and place inside the vacuum packing bags.
Combine sake, soy souce, mirin, sugar, and water and stir until sugar is dissolved. Divide the broth between three bags with pork equally. Divide prepared garlic, ginger, and scallions ibto three equal portions and add them to the bags.
Vacuum pack each portion of pork.
Cook for 3 hours, 140F/60C. When ready, prepare a big bowl with ice bath (ice and water 1:1). Keep the pork loin vaccum packed.
Use ice bath to quickly cool down cooked pork to room temperature and then refrigerate for 12-24 hours — it'll continue being marinated. Slice it thinly when cold and use ramek broth to reheat it in the bowl.