Pound the pork lightly to an even thickness using the back of a knife. Season both sides with pepper and salt. Coat each piece in flour, dip into the beaten egg, then press into panko breadcrumbs until well coated. Set aside.
Heat oil in a wok or medium pot over medium heat (fill no more than halfway). Deep fry the pork for 3-4 minutes per side or until golden and cooked through. Drain on paper towels and set aside.
To make curry, heat 2-3 tablespoons of oil in a medium saucepan over medium-high heat. Add the onion and cook until golden. Stir in carrots and sauté for another 2-3 minute.
Add water, bring to boil, then reduce the heat to medium. Cover loosely with a lid and simmer for 10 minutes.
Turn the heat to low. Add the curry blocks and stir until completely dissolved. Mix in soy sauce, mirin, tomato sauce and Worcestershire sauce. Simmer gently for another 5 minutes, Stirring occasionally. Adjust seasoning if needed.
Spoon steamed Japanese rice into bowls, ladle curry over the top, and place sliced pork katsu on one side. Drizzle with tonkatsu sauce if desired and garnish with parsley.
