Slice pork loin thinly and season with salt and pepper.
Coat the pork with flour, beaten egg, and breadcrumbs in that order.
Pour enough cooking oil into a pan and preheat to 170°C.
Fry the pork until golden brown and set aside.
Thinly slice the onion.
Add tsuyu, water, and sugar to a pan and bring to a boil.
Add the sliced onion and fried pork cutlet to the pan and simmer.
Pour beaten egg over the top, cover, and cook until half-cooked.
Place everything over rice to serve.