Gather all the ingredients.
Cut pork belly into 4 inch length by 1-2 inch thickness as shown below. Rub salt onto all sides of the pork belly and set aside.
Thinly slice ginger and jalapeno. Set aside.
Grind garlic with a grinder or a garlic press and set side.
In a medium sized stove top pot, add water, Japanese sake, Soy Sauce, sweetener , sliced ginger, sliced jalapeno, grated garlic and place on low heat.
In the meantime, add cooking oil into a cast iron pan and bring up to temp. Once up to temperature, carefully add pork belly. Sear all 4 sides for 1 minute per side. Once seared, transfer to a holding plate.
Now bring sauce in medium sized stove top pot from step 5) to a boil. Once boiling, add seared pork belly inside. Reduce to low heat and cook 7/8 the way covered for 1 hour. Just make sure to mix around every now and then to avoid burning the bottom.
In the meantime, slice green onions and set aside.
After 1 hour has passed, remove the cover and raise heat to medium-low. Cook for an extra 10-15 minutes to reduce the sauce. Keep an eye on this as this can burn very easily.
Once most of the sauce is reduced, remove from heat. Slice pork belly long ways and transfer to serving plate. Garnish with green onions and enjoy!